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CANADA # GRAPHITE 



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^CANADA 

DEPARTMENT OF MINES 

Hon. MARTifr Burrell, Minister; R. G. McConnell, Deputy Minister. 



mines branch 

Eugene Haanel, Ph.D., Director. 



GRAPHITE 



BY 

Hugh S. Spence, M.E. 




OTTAWA 

THOMAS MULVEY 

PRINTER TO THE KING'S MOST EXCELLENT MAJESTY 

1920 



No. 511 



67945-1 



Ill 






LETTER OF TRANSMITTAL. 

Dr. Eugene Haanel, 

Director, Mines Branch, 
Department of Mines, 
Ottawa. 

Sir, — I beg to submit, herewith, my report on the graphite industry 
in Canada, together with details relating to the occurrence, distribution, 
refining, and uses of graphite. 

I have the honour to be, Sir, 

Your obedient servant, 

(Signed) Hugh S. Spence. 
Ottawa, May 20, 1919. 



67945—11 



CONTENTS. 

PAGE. 

Introductory 1 

CHAPTER I. 

History of Graphite and description of its chemical and physical properties 3 

History 3 

Chemical and physical properties 4 

CHAPTER II. 

Mode of occurrence and origin of Graphite 9 

CHAPTER III. 

Composition and economic importance of Graphite ores 13 

CHAPTER IV. 

Graphite in Canada 18 

General 18 

Types of deposits. 19 

Mining methods 21 

Graphite mines and occurrences . 22 

Province of British Columbia 22 

Province of New Brunswick ." 22 

Province of Nova Scotia '. 24 

Province of Ontario 25 

Frontenac county 26 

Township of Bedford. 26 

Haliburton county 26 

Township of Cardiff 26 

Township of Monmouth 27 

Lanark county 28 

Township of North Burgess 28 

Township of North Elmsley 29 

Renfrew county 35 

Township of Brougham 35 

Township of Lyhdoch 39 

Additional Graphite localities in Ontario 39 

Lake of the Woods. (Carbonaceous schists) 41 

Province of Quebec 42 

Argenteuil county 44 

Township of Grenville 44 

Township of Wentworth 46 

Labelle county 46 

Township of Amherst 46 

Township of Buckingham 48 

Township of Lochaber 58 

Hull county 58 

Township of Low 58 

Maniwaki Indian Reserve 60 

Additional Graphite localities in Quebec 60 

Baffin island 61 

CHAPTER V. 

Concentrating and refining of Graphite 63 

Plumbago 63 

Amorphous Graphite 63 

Flake Graphite 64 



VI 

PAGE 

Concentration by dry methods 67 

Pneumatic j igs 68 

Air classifiers 73 

Rolls and screens 74 

Electrostatic machines 78 

Concentration by wet methods 80 

Buddies. 80 

Mechanical washers 83 

Log washers 83 

Rake washers 84 

Wet tables . 85 

Flotation 86 

Frothing oil flotation 86 

Callow system , 90 

Minerals Separation system 98 

Simplex system 99 

K. and K. system 100 

Surface tension or film flotation 101 

Miscellaneous 108 

Refining of Graphite concentrates 110 

Summary Ill 

Chemical refining of Graphite 112 

CHAPTER VI. 

Artificial Graphite 114 

CHAPTER VII. 

Uses of Graphite 119 

Crucibles 119 

Clays for crucibles 125 

Manufacture of crucibles 131 

Other Graphite refractory products 144 

Pencils 144 

Foundry facings 149 

Dry batteries 150 

Electrotyping Graphite 150 

Graphite brushes 151 

Graphite electrodes 154 

Graphite for lubricating 155 

Graphite paints '. 158 

Stove polish , 159 

Boiler Graphite 159 

Graphite for powder glazing and shot polishing * 160 

Subsidiary uses 160 

CHAPTER VIII. 

The Canadian Graphite industry 162 

Production, exports, imports, etc 162 

Domestic consumption of Graphite 167 

General review of the industry 167 

Review of market conditions 1914-1918 170 

CHAPTER IX. 

Sources of the world's Graphite supply 174 

Austria 174 

Ceylon 175 

Chosen (Korea) 177 

Germany 177 

Italy 178 

Madagascar . 178 

Mexico 180 

South Africa 180 



vu 

PAGE 

Spain 180 

United States 181 

Alabama 181 

New York. . 182 

Pennsylvania ; 183 

Crystalline Graphite or Plumbago 183 

Alaska J. 183 

Montana 183 

Flake Graphite 184 

California and Texas 184 

Amorphous Graphite 184 

Colorado 184 

Michigan 184 

Nevada 184 

Rhode Island 184 

Miscellaneous Localities 184 

World's production of Graphite ; 185 

Artificial Graphite 187 

CHAPTER X. 

Determination of the carbon content of Graphite and Graphite ores.... 188 

Combustion method 189 

Fusion method 191 

Absorption method 191 

Re-carbonating method 191 

Further notes on analytical methods 192 

Appendix .' 195 

Bibliography of Canadian Graphite 195 

Index 197 



Plate I. 

II. 

III. 

IV. 

V. 

VI. 

VII. 

VIII. 

IX. 
X. 

XI. 

XII. 
XIII. 

XIV. 

XV. 

XVI. 

XVII. 

XVIII. 

XIX. 

XX. 

XXI, 
XXII. 



ILLUSTRATIONS, 

Photographs. 

Canadian flake graphite ore End 

Foliated plumbago r 

Fibrous or columnar plumbago 

Radiated, lamellar crystals of graphite 

Foliated plumbago 

Mill of National Graphite Company, Mumford, Ont . 

Mill of Tonkin-Dupont Graphite Company, Wilberforce, Ont.. 
Method of working graphitic limestone ore-body, township 

of Monteagle, Ont 

Mill on Timmins property, township of North Burgess, Ont . . 
Open cut at workings of Globe Graphite Mining and Refining 

Company, township of North Elmsley, Ont 

100-foot level at mine of Globe Graphite Mining and Refining 

Company, township of North Elmsley, Ont 

Needle-flake graphite ore, township of North Elmsley, Ont.. . . 
Mill of Globe Graphite Mining and Refining Company, Port 

Elmsley, Ont 

Mill and part of surface plant of Black Donald Graphite 

Company, township of Brougham, Ont 

North end of east or hanging wall stope, Black Donald mine, 

township of Brougham, Ont 

Main pit at Miller or Keystone mine, township of Grenville, 



Qi 



Mill of Graphite, Ltd., township of Amherst, Que 

Folded structure in gneiss, township of Buckingham, Que 

Mill of New Quebec Graphite Company, Buckingham, Que. . . 
Mill and workings of Bell Graphite Company, township of 

Buckingham, Que 

Large sized graphite flakes from township of Buckingham, Que 
Mill of Plumbago Syndicate, township of Buckingham, Que. . . 



Vlll 



Plate XXIII. 

XXIV. 

XXV. 

XXVI. 

XXVII. 

XXVIII. 

XXIX. 

XXX. 

XXXI. 

XXXII. 

XXXIII. 

XXXIV. 

XXXV. 



XXXVI. 

XXXVII. 

XXXVIII. 

XXXIX. 

XL. 

XLI. 

XLII. 

XLIII. 

XLIV. 

XLV. 

XLVI. 

XLVII. 

XLVIII. 

XLIX. 

L. 

LI. 

LII. 

Lin. 

LIV. 

LV. 

LVI. 



Mill of Buckingham Graphite Company, township of Buck- 
ingham, Que End. 

Pegmatite intruded into gneiss, Walker mine, township of 

Buckingham, Que '. . . „ 

Mill of Consolidated Graphite Mining and Milling Company, 

township of Buckingham, Que " 

Foliated plumbago from Lake harbour, Baffin island " 

Sectional view of Raymond High-Side mill and separator " 

Type of kiln used for drying graphite ore . " 

Krom pneumatic jig " 

Hooper pneumatic concentrator " 

Type of rolls used in Canadian mills " 

Installation of King Bee rolls at a mill in the Buckingham 

district, Que " 

Sutton, Steele and Steele di-electric separator " 

Details of Sutton, Steele and Steele di-electric separator " 

Section of mill showing Krupp-Ferraris tables, slime tables and 
hydraulic classifiers, New Quebec Graphite Company, 

Buckingham, Que " 

Callow pneumatic flotation cells in operation " 

Seek polishing rolls for finishing flake graphite " 

Machine for mixing crucible bodies: back view " 

Machine for mixing crucible bodies: front view " 

Pull-down and jigger used in making crucibles " 

Pull-down and jigger used in making crucibles " 

Crucibles as removed from moulds " 

Types of crucibles used in melting non-ferrous metals " 

Types of crucibles used in tilting furnaces " 

Defects developed in crucibles by improper usage " 

Type of crucible used in melting steel " 

Bottom-pour crucible " 

Brazing crucibles for dip-brazing " 

Type of retort used in the smelting of gold, silver, zinc, etc ... " 
Funnel or extension tops for increasing the capacity of 

crucibles, and pyrometer shields " 

Types of graphite stoppers and nozzles for steel-pouring 

ladles 

Types of phosphorizers used in the manufacture of phosphor 

bronze " 

Types of stirrers, skimmers, and dippers " 

Types of graphite commutator brushes " 

Types of Nigrum oilless bushings " 

Types of Bound Brook oilless bushings " 



Fig. 1 



4. 
4a. 

5. 

6. 

7. 

8. 

9. 
10. 
11. 
12. 
13. 
14. 



Drawings. 

PAGE 

Surface plan at mine of Globe Graphite Mining and Refining Company, 

township of North Elmsley, Ont 30 

Diagram of ore-body at mine of Globe Graphite Mining and Refining 

Company, township of North Elmsley, Ont 31 

Sections through workings at mine of Globe Graphite Mining and Refining 

Company, township of North Elmsley, Ont 33 

Plan of workings, Black Donald Graphite Company, township of 

Brougham, Ont 38 

Profile of workings, Black Donald Graphite Company, township of 

Brougham, Ont 38 

Surface plan of graphite showings, township of Lyndoch, Ont 40 

Plan and section of graphite deposit, township of Wentworth, Que 47 

Geologic relationships at Dominion mine, township of Buckingham, Que. . 51 

Plan of workings at Walker mine, township of Buckingham, Que 56 

Sketch of occurrence of plumbago, Lake harbour, Baffin island 61 

Installation showing Raymond mill for grinding graphite 65 

Section through Hooper pneumatic concentrator 68 

Section through Krom pneumatic jig 69 

Sutton, Steele and Steele three section jig 70 

Flow sheet of Sutton, Steele and Steele dry concentration installation 71 



IX 

PAGE 

Fig. 15. Result of test made on Alabama graphite ore by Sutton, Steele and Steele 

dry process 72 

16. Section through type of air classifier used in Alabama mills 73 

17. Flow sheet of dry concentration system employing rolls . . . . 76 

18. Flow sheet of dry concentration system by means of a combination of 

rolls and tables 76 

19. Flow sheet of dry concentrating and finishing plant for flake graphite. ... 77 

20. Section through Huff electrostatic separator 80 

21. Flow sheet showing mill system using buddies as installed in a New York 

mill 81 

22. Flow sheet of combined wet and dry concentrating system as installed 

in an Ontario mill 82 

23. Flow sheet of mill employing log washer concentration, Byers, Pennsyl- 

vania , 83 

24. Flow sheet of wet concentration system using rake washers in a Pennsyl- 

vania mill 84 

25. Ferraris type of wet table 85 

26. James type of wet table 86 

27. Flow sheet of wet concentration system using Ferraris tables as installed 

in a Quebec mill 87 

28. Flow sheet showing Callow pneumatic flotation system as installed in an 

Alabama graphite mill 91 

29. Flow sheet of mill using Callow penumatic flotation concentration 92 

30. Flow sheet of Minerals Separation oil flotation system as installed in an 

Alabama mill 99 

31 Flow sheet showing Simplex oil flotation system as installed in an Alabama 

graphite mill 100 

32. Section through Simplex washer 100 

33. Section through original Munro washer. 101 

34. Section through New Munro washer 102 

35. Section through Colmer washer 103 

36. Flow sheet of surface tension concentration installation using Munro 

washers in an Alabama mill 104 

37. Flow sheet of surface tension concentration installation using Munro 

washers in an Alabama mill 105 

38. Flow sheet of surface tension flotation installation using Colmer washers 

in an Alabama mill 107 

39. Section through electric furnace for the production of artificial graphite. . 116 

40. Section through electric furnace arranged for graphitizing carbon electrodes 

of rectangular section 117 

41. Section through electric furnace arranged for graphitizing round carbon 

electrodes 117 

42. Type of automatic graphite cylinder lubricator 155 

43. Diagram showing production of graphite in principal countries in 

1907-1917 185 

Maps. 

No. 513. Graphite occurrences in Bedford, Loughborough, Burgess and Elmsley 

townships, Ont 26 

514. Graphite occurrences in Monmouth, Cardiff, Monteagle and Dungannon 

townships, Ont 26 

515. Graphite occurrences in Brougham and Blithfield townships, Ont 36 

516. Graphite occurrences in Grenville and Wentworth townships, Que 44 

517. Graphite occurrences in Amherst township, Que 46 

518. Graphite occurrences in Buckingham and Lochaber townships, Que 48 



GRAPHITE. 

INTRODUCTORY. 

Graphite occurs somewhat plentifully in certain belts in the crystalline 
limestones and gneisses of the Archaean (Grenville) series of eastern Canada, 
the mineral being found both in the disseminated flake and vein (plumbago) 
form. Deposits of the latter type are known, and have been worked in 
a small way, on the south shore of Baffin island. Amorphous graphite, 
also, is common in the slates of Nova Scotia and New Brunswick, and there 
was formerly an important output of this class of material from workings 
near St. John, N.B. 

Unfortunately, the veins of plumbago (the most valuable form of 
graphite, and greatly in demand for crucible manufacture) are narrow, 
and their exploitation is unlikely ever to prove a profitable undertaking. 
Small amounts of plumbago have, from time to time, been taken from 
shallow workings on such veins, but the total quantity thus obtained 
is insignificant. 

The commercial flake ores are represented both by crystalline lime- 
stone, ranging in graphite content up to about 8 per cent, and' gneiss, 
which sometimes contains as much as 30 per cent of graphite. The average 
run-of-mine in the case of the latter type of ore is, however, only 10 to 15 
per cent graphite. Both classes of ore commonly grade insensibly into 
barren country rock. 

While mining and milling of Canadian flake ores commenced as far 
back as 1866, the industry has never assumed any large proportions. 
This is due, largely, to the failure that has for years attended efforts to 
evolve an efficient and economical concentrating process for these ores. 
A great variety of methods have been tried, but none can be said to have 
proved conspicuously successful. The result has been that few operators 
have continued work for any length of time; and of the dozen or so mills 
that have been erected within the last twenty years, not more than two 
or three have been on the list of active producers at any one time. In the 
last two or three years, however, considerable experimentation has been 
carried out_ on graphite ores with the frothing oil flotation method of 
concentration, and the results achieved have shown that this method offers, 
probably the cheapest and most efficient means of extracting graphite 
from its ores that has yet been devised. A number of American mills 
have adopted one or other of the various systems of oil flotation, with 
highly satisfactory results, and, at the time of writing, the process is being 
tried out in one Canadian mill and is under consideration by others. 
Since the better grades of Canadian flake ores average 10 to 15 per cent 
graphite as against 3 to 6 per cent in American ores, profits per ton of ore 
treated would be proportionately greater. It is to be hoped that oil flota- 
tion may prove the means of placing the flake graphite industry in this 
country on a more satisfactory basis than heretofore. 

The question of graphite supplies for the crucible trade, which at the 
time of the outbreak of the war was estimated to consume probably 75 
per cent of the world's output of graphite, became of urgent importance 

1 



to American metallurgical industries in 1915. Owing to the embargo 
placed upon exports of Ceylon plumbago and Madagascar flake by the 
British and French Governments, respectively, American crucible manufac- 
turers were faced by a serious shortage of graphite, and a great expansion 
in the American — more particularly the Alabama — flake graphite industry 
took place. Between 1916 and 1918, more than forty new graphite mills 
sprang up in this State, a great variety of concentrating methods being 
employed in the different plants. 

With the object of securing the latest data on milling methods, details 
of manufacture of graphite products and the requirements of the trade, 
as well as information regarding the graphite situation generally, the 
writer in 1918-19 visited the principal mines and mills in Alabama, New 
York, and Pennsylvania, and also a number of plants in the United States, 
manufacturing crucibles, pencils, stove polish, foundry facings, paints, 
commutator brushes, artificial graphite, etc. The principal graphite 
importers and brokers in New York were interviewed; Government 
departments in Washington were visited; methods in assay and analytical 
laboratories were studied; and a number of other authorities on graphite 
and the graphite industry were conferred with. 

The writer desires to express his appreciation of the universal courtesy 
shown him in the course of the above-mentioned investigation, also his 
grateful acknowledgment for the information so freely afforded him by 
individuals and managements, who, by their cordial co-operation, have 
assisted so materially in the preparation of this report. 1 

iNoTE. — This report is intended to take the place of Report No. 18, Graphite: Its Properties, 
Occurrence, Refining and Uses, by F. Cirkel, published by the Mines Branch in 1907, and which 
i s now out of print. 



CHAPTER I. 

HISTORY OF GRAPHITE, AND DESCRIPTION OF ITS CHEMICAL 
AND PHYSICAL PROPERTIES. 

History. 

Graphite 1 was known in very early times, though its use was probably 
limited to decorative purposes, in the same way as red earthy hematite: 
both minerals have been found in prehistoric burial places in Europe, and 
urns and pottery coloured by graphite are also recorded from ancient 
graves. 

Graphite first came into general use, however, many centuries later, 
and it is first mentioned in the Middle Ages as a substance for use in draw- 
ing. It was regarded as somewhat of a mineral curiosity, and was doubt- 
less often confused with other minerals, such as molybdenite, as well as 
with artificial products designed for drawing or writing. Despite the fact 
that graphite has been known for so long, its true nature and identity were 
not recognized until the end of the 18th century. The generally accepted 
idea was that graphite contained lead, and the names "black lead" and 
"plumbago" were applied to it on this assumption. There is little doubt 
that there was much confusion among the early chemists and mineralogists 
over the identity of the mineral in question, and various substances were 
investigated and described under the same name. 

Possibly the first specific reference to pencils is that contained in a 
treatise on painting, written by Cennini, of Florence, about the year 1400. 
Cennini describes a pencil composed of two parts of lead and one part of 
tin, and the "lead" has been commonly supposed to have been graphite; 
this, however, would appear to be decidedly doubtful. 

Agricola (1495-1550), describes refractory crucibles made of graphite, 
and it would seem that such crucibles were in general use by the alchemists 
in their attempts to transform the t)ase metals into gold. 

Conrad Gesner (1565), in his treatise on the nature of minerals and 
rocks, makes mention of a writing pencil composed of "English antimony", 
by which was probably meant the soft graphite obtained from the famous 
mines at Borrowdale, in Cumberland. These mines were opened in 1554, 
and for over three centuries furnished a superlative grade of pencil graphite. 

Heinrich Pott (1692-1777), a German chemist, showed that "plum- 
bago" contained no lead; but there is some doubt whether he actually 
experimented with graphite or with molybdenite, because, like his fellow 
chemist Quist, be did not distinguish in his writings between the two 
minerals. 

It was Karl Wilhelm Scheele (1742-1786) who first made a thorough 
investigation of both graphite and molybdenite, and finally showed in 

1 From the Greek " graphein ", to write. Other names for the mineral are plumbago, black 
lead, kish, potelot, crayon noir, carbo mineralis. " Plumbago " and " black lead " are names 
that still are applied to graphite by the trade, though each has a slightly different significance. 
While the name " graphite " is commonly used for the crystalline flake mineral, " plumbago " 
is applied to the massive, vein material, such as obtained from Ceylon; while " black lead " 
is often employed for the amorphous material that enters largely into stove polish, lead pencils, 
etc. These different terms are merely a matter of usage and convenience to distinguish the three 
slightly different forms of the same substance. 



what respeGts they differed. Scheele demonstrated the carbon content 
of graphite by igniting it in a current of oxygen, and also dissolved molyb- 
denite with nitric acid, obtaining molybdic oxide. 

The name "graphite" was first given to the mineral by the minera- 
logist Werner in 1789. 

Chemical and Physical Properties. 

The element carbon exists in three ailotropic forms, two of which, 
graphite and diamond, are found in nature as minerals. Graphite 1 , however, 
differs to such a degree from diamond and amorphous carbon (charcoal), 
both in its outward characteristics, such as form, colour, hardness, etc., 
as well as in many of its properties, that Brodie considered it to be a distinct 
element, which he termed "graphon". 

The three forms of carbon, charcoal, graphite, and diamond, may be 
readily distinguished by chemical and physical tests. The specific gravity 
of charcoal is 1-3 to 1-9; of graphite, 2-1 to 2-3, and of diamond 3-5. 
Chemically, a ready means of differentiating between the three forms is 
to treat with potassium chlorate and concentrated nitric acid in the pro- 
portion of one part of the substance to be tested, three parts of potassium 
chlorate and sufficient acid to render the mass liquid. The mixture is 
then heated on a water bath for several days, when the diamond is found 
to be entirely unaffected. The graphite is converted into golden-yellow 
flakes of graphitic acid and the amorphous carbon is altered to a brown 
substance soluble in water 2 . Many so-called graphites, when treated in 
this way, are shown to be charcoal, natural coke, or even coal or carbona- 
ceous shale. Coal or carbonaceous shale may be detected by the amount 
of volatile matter present, while all of the enumerated adulterants are 
conspicuous by reason of their low ignition temperatures, as compared 
with graphite. A further means of distinguishing between graphite and 
coke or retort carbon is to note their behaviour when fused with sodium 
sulphite: graphite does not reduce this salt, whereas coke and retort 
carbon react very actively with it. 

Natural graphite seldom occurs in well formed crystals (e.g. in certain 
crystalline limestones), but is usually found in laminated or more or less 
flaky aggregates disseminated in schistose rocks. It also occurs in veins, 
in which case the mineral usually exhibits either a foliated or fibrous 
structure. Eartlvy, amorphous graphite, commonly occurs in bedded 
deposits, and is then considered to be the result of the metamorphism of 
coal or carbonaceous material. 

Graphite, as it usually occurs, is a black, lustrous mineral generally 
held to crystallize in the hexagonal system, with rhombohedral symmetry. 
Some authorities, however, claim it to be monoclinic. The crystals have 
tabular form, are six-sided, and the faces are commonly striated. On 
account of the softness of the mineral, the faces are seldom very distinct. 
Very perfect crystals are found in the crystalline limestone of Pargas, in 
Finland, but the best specimens have been obtained from meteorites. 



1 See Donath, E., Der Graphit, Leipzig, 1904, and Haenig, A., Der Graphit, Wien, 1910. 

2 Donath (Der Graphit, p. 3) considers it not absolutely certain that chemically pure 
amorphous carbon yields a red-brown solution when treated as described, but suggests that the 
coloration may be due to impurities in the material. 

The formula C28H10O16 has been proposed by Berthelot for graphitic acid prepared from natural 
graphite. It is insoluble in all solvents, and its yellow, mica-like scales alter upon drying to a 
brown mass. 



Twinned crystals or crystals in parallel intergrowth have been recorded 
by W. Luzi. 

When well crystallized, the flakes have a black to steel-grey, metallic 
lustre, while the amorphous variety is matte, black and earthy. The streak 
is black and lustrous, the hardness 1, and the specific gravity 2 • 1 to 
2-3. The mineral is easily sectile, and is flexible but not elastic. Owing 
to its softness, it marks other substances very easily and is greasy to the 
touch. It is a good conductor of heat and electricity. The flakes have a 
perfect basal cleavage and are opaque, even in the thinnest scales. Its 
temperature of fusibility is unknown, but is probably above 3000°C. It 
is combustible in the presence of oxygen at between 620°C and 670°C, but 
is not altered by heating in a vessel free of air. 

Chemically, graphite is pure carbon, and it is thus identical in compo- 
sition with charcoal and the diamond. Impurities are almost always 
present in natural graphite, and usually consist of included foreign mineral 
substance, such as clay, oxide of iron, calcite, quartz and mica. A small 
amount of hydroxy 1, also, is not infrequently to be found in natural 
graphites. 

Graphite is veiy resistant to weathering influences, and perfectly 
bright flakes of the mineral are commonly to be found in the surface soil 
formed by the disintegration of graphite-bearing rocks. 

With reference to the specific gravity of graphite, Donath gives the 
following list of determinations on samples from a number of localities: — 

Ceylon (1) 2-257 

Borrowdale 2-286 

Oberer Jenisei 2-275 

Upernivik 2-298 

Arendal 2-321 

Ticonderoga 2-17 

Ceylon (2) 2-246 

Blast furnace graphite 2-30 

The specific heat of graphite is 0-2019, and Weber has found it to 
vary for different temperatures as follows: — 
At -50°C 1138 
+61°C 0-1990 
+ 977°C 0-4670. 
That of diamond for approximately the same temperatures was found 
to be : — 

At -50°C 0-0635 
+ 58°C 0-1532 
+ 1000°C 0-4589. 
The above values for graphite were determined on pure Ceylon graphite 
containing only 0-38 per cent ash. 

At the lower temperatures, the specific heat of diamond is thus seen 
to vary considerably from that of graphite and amorphous carbon, both 
of the latter being approximately the same. As the temperature rises, 
however, the values for all three modifications become more nearly equal, 
and at 1000°C they are practically identical. 

The calorific values for different forms of carbon have been determined 
as follows : — 

Graphite per gram. 7779 • 45 Cal. 

Diamond " 7770-00 " 

Blast furnace graphite " 7762 • 30 " 



Graphite is highly resistant to attack by most chemical reagent? 
Fusion with alkaline carbonates produces carbon monoxide, which puf 
through the molten material and ignites as fast as formed, the graphi 
being consumed in reducing the carbonate. Pure molten caustic alka 
at a low red heat, does not attack graphite appreciably, but separates 
from its mineral associates and leaves the graphite in a free and purif 
condition. Pure graphite is not altered by heating in a stream of dry 
chlorine gas, nor is it affected by hydrochloric or hydrofluoric acids. 

High grade graphite is only slowly attacked by molten potassium 
nitrate at a low red heat. Certain metallic oxides upon the surface of 
molten metal or alloys at very high temperatures have a tendency to 
oxidize or burn out graphite, and the same holds for strongly oxidizing slags 
which have high melting points. For this reason, graphite crucibles used 
in steel work rarely average more than six or seven heats, while those 
employed in melting brass give as many as twenty to twenty-five heats. 

Graphite may be completely oxidized by a mixture of chromic and 
sulphuric acids. It may also be converted to carbon dioxide in a combus- 
tion furnace. A far simpler method, however, and the one usually followed 
in making a determination of the carbon content of a graphite sample, is 
to heat the graphite in a platinum crucible over the full heat of a Bunsen 
burner, while admitting a stream of oxygen. 

In the assay of graphite, the samples should always be graded according 
to the apparent carbon content; low grade material, such as a graphite 
ore, requiring different treatment to a sample of refined graphite. The 
chief impurities in the refined graphite of commerce, are moisture, sulphur 
(in the form of pyrites), calcite, quartz, and mica. Sulphur is undesirable 
in graphite for crucibles used in melting silver or high grade alloys, and 
for this reason pyrites should be eliminated as far as possible in the milling 
as the combined iron gives rise to red spots on annealing. 

It is common practice to term certain finely divided graphites "amor- 
phous", in contradistinction to the coarser, flake or crystalline variety. 
The term "amorphous" graphite is really a misnomer, since all graphite 
is crystalline carbon, and, as shown above, is distinct from amorphous 
carbon, which does not yield graphitic acid on treating with potassium 
chlorate and nitric acid. So called "amorphous" graphite is really crys- 
talline graphite whose particles are so small as to be indistinguishable to 
the eye, and which consequently has a dull or earthy appearance. Under 
the microscope, these earthy graphites are seen to be made up of very 
finely-crystalline material, and are, thus, cryptocrystalline. 

Certain graphites, however, as, for instance, the Bohemian, which is 
an earthy so called "amorphous" variety, yield graphitic acid in the nature 
of a yellow powder, while that obtained from Ceylon plumbago is in the 
form of lamellar crystals. On decomposing by heat, the powdery graphitic 
arid yields a material resembling lampblack, while that obtained from the 
crystalline acid is lighter in colour and does not appear to be in such a fine 
state of division. It would appear, therefore, that there may be some 
difference in the molecular structure of certain of the "amorphous" and 
"crystalline" graphites, but the subject has not been sufficiently investi- 
gated to enable any definite distinction to be drawn between the two types. 
On the other hand, the loose application of the term "amorphous" to many 
finely crystalline graphites as, for example, that from the Black Donald 
mine, in Ontario, is decidedly erroneous. 



It was formerly suggested that several varieties of graphite existed, 
the distinction between them being based on their different behaviour when 
treated with chemicals. For instance, certain graphites, when moistened 
with fuming nitric acid and then heated, swell up and assume vermiform 
shapes, having a circumference of \" to \" and a length sometimes of several 
inches. These forms have a steel grey colour and metallic lustre, and are 
bent and twisted in regular curves : their regular structure imparts to them 
a very characteristic appearance, and the volume of such so called "graphite 
worms'/ is often a hundred or more times greater than that of the original 
graphite from which they were formed. It is supposed that the cause of 
this phenomenon is the capillary structure of the flakes, which permits 
them to absorb the acid readily. On heating, the gas generated from the 
acid exfoliates the graphite. The graphites that yield such forms are, 
therefore, not believed to be essentially distinct from those that show no 
such reaction. The former were originally classed by Luzi, who investi- 
gated many graphites along these lines, as true "graphites", while the latter 
he termed "graphitites". The name "graphitoid", also, has been applied 
to a black, earthy pigment containing nitrogen and water, which burns 
in the Bunsen flame, and which even under the highest power of the micro- 
scope exhibits no crystalline structure. ' 

Weinschenk, who made an investigation of many graphites, disputes 
the existence of any such distinct modifications of natural graphite, and 
regards the different behaviour of the graphites from various localities 
as due usually to their structure. The above distinctions are seldom 
made nowadays, and the matter of these differences of behaviour under 
certain conditions possesses only academic and little technical importance. 
The nitric acid treatment has, however, been employed as a means of 
cleaning natural graphite and obtaining a product of exceptional purity 
and in a very fine state of division. 

When finely powdered graphite is heated with a mixture of one part of 
nitric and four parts of strong sulphuric acid, or when a mixture of four- 
teen parts of graphite and one part of potassium chlorate is warmed with 
seventy-eight parts of strong sulphuric acid, the graphite assumes a purple 
tint, but on washing regains its original colour. It is, however, no longer 
graphite, but contains in addition oxygen, hydrogen, and sulphuric acid. 
When this is heated to redness it swells up with a copious evolution of gas 
and then falls to an extremely fine powder of pure graphite, which has a 
specific gravity of 2-25 — (so called "Brodie's graphite"). 

The above process has been employed for the purpose of purifying 
natural graphite. With this object it is first ground fine and the powder 
well washed in troughs to remove as much of the earthy gangue as possible. 
The concentrates are then treated as described above and the resulting 
material passed on to the surface of water, when the graphite floats off 
and the impurities sink. Flake graphite is more readily purified by this 
process than the powdery forms. The latter may be similarly treated, 
however, if a small amount of sodium fluoride be added to the mixture 
as soon as the evolution of chlorine trioxide gas has ceased; by this 
means, the silica is removed as silicon tetrafluoride. 

Artificial graphite, the product of the electric furnace, does not possess 
the property of swelling up when treated with nitric acid, but that separating 
out from fluid metals, by reason either of simply the high temperature or 
on account of chemical reaction, possesses it very markedly. 

67945—2 



8 

Artificial graphite may be either amorphous or crystalline. Its 
specific gravity ranges from 2 to 2-25, and its temperature of combustion 
in oxygen is in the neighbourhood of 660 C C. The resistance to oxidation 
of artificial graphite produced in the electric furnace is proportional to the 
temperature at which it was formed. 

Ceylon graphite, which is more or less readily oxidized, may be made 
more refractory by subjecting it to great heat. 

For fuller details regarding the chemical, physical, and other properties 
of graphite, the reader is referred to pages 1 to 29 of Donath's work already 
cited, and to pages 6 to 19 of Haenig's monograph. Much of this informa- 
tion is of scientific rather than technical importance and, as such, has not 
been included in the present report. 



CHAPTER II. 

MODE OF OCCURRENCE AND ORIGIN OF GRAPHITE. 

The natural graphites are usually divided into three classes, according 
to the character of the mineral. These divisions comprise disseminated 
flake, crystalline (plumbago), and amorphous. As pointed out elsewhere 
(p. 6), what is sometimes termed " amorphous " graphite is in reality 
extremely finely-divided flake graphite, and the term " amorphous " 
should not, strictly, be applied to any graphite, since all " graphites " 
are in their physical characteristics essentially distinct from amorphous 
carbon. As used, however, the term " amorphous " is applied to those 
graphites which exhibit no semblance of crystalline structure, being so 
finely divided as to be more or less earthy in character, and which for this 
reason cannot be utilized for many of the purposes to which the flake or 
crystalline varieties are adapted. The distinction between " flake " and 
" crystalline " graphite (both are essentially crj^stalline in character) 
lies in the mode of occurrence of the two varieties and the consequent 
difference in form assumed by them. Flake graphite, as the name indicates, 
is the scaly or lamellar form of the mineral, commonly found dissemi- 
nated in metamorphic rocks, such as crystalline limestones, gneisses 
and schists. In such cases, each flake is a separate individual and has 
crystallized as such in the rock. Crystalline graphite, on the other hand, is 
the graphite found either in the form of more or less well-defined veins or as 
pockety accumulations along the intrusive contacts of pegmatites (usually) 
with limestones, schists, etc. Both types of occurrence are fundamentally 
similar, in that they represent fissure or fracture-filling by graphite, 
the shape only of the ore-body being different and the amount of foreign 
mineral substance in the form of in-crystallized, contact-metamorphic 
minerals being greater in; the latter case than in the former. The graphite 
of such deposits is of two types, foliated or bladed and columnar (fibrous). 
(See Plates II and III) . Vein graphite generally requires no other prepar- 
ation for the market than is involved in a hand-cobbing process, followed 
possibly by screening. By these means, a product running 90 per cent 
graphitic carbon may readily be secured. 

Amorphous graphite is commonly found in the form of minute particles 
more or less uniformly distributed in feebly metamorphic rocks, such as 
slates and shales, or in beds consisting practically entirely of graphite. 
The latter represent usually metamorphosed coal seams, and carry as high 
as 80-85 per cent graphitic carbon, while the former, being altered carbon- 
aceous sediments, commonly range from 25 to 60 per cent. The graphite 
content of such amorphous deposits is dependent on the amount of carbon 
originally present in the sediments, and there is no evidence of any enrich- 
ment being caused by the intrusive rocks that have been the metamor- 
phosing agencies in some cases. Certain amorphous graphite deposits 
have undoubtedly been formed by the agency of igneous intrusives, while 
others are probably the result of dynamic metamorphism. 

Most, if not all of the world's deposits of flake and crystalline graphite 
occur in rocks of Pre-Cambrian or early Palaeozoic age. Crystalline 
limestones, gneiss (often calcareous and associated with limestones) 

67945—21 



10 

and schists are the more usual types of rock in which the economic deposits 
of flake graphite occur, and in many cases the series has been intruded 
extensively by rocks of pegmatitic or granitic character. The vein graphites 
are found in rocks of similar character to the above, but the rock enclosing 
them is not necessarily graphitic; in fact, in the majority of cases, the wall 
rock of such veins carries little or no graphite, and the deposits thus assume 
the character of true lodes. Graphite veins seldom attain an important 
width, however, anything over 10-12 inches being exceptional, and the 
majority measuring considerably less than this. 

It is convenient to class with the vein graphites those pockety bodies 
of crystalline graphite sometimes met with in the Pre-Cambrian gneiss- 
limestone series of Quebec and New York State. 1 Such bodies are far 
less common than the true vein type, and are characterized by their 
irregular form and the abundance of foreign mineral substance intergrown 
with the graphite. The most common of such minerals are scapolite, 
idocrase, pyroxene, calcite and sphene, and their association with the 
graphite is so close as to render milling of a large proportion of the ore 
necessary. In the case of the vein graphites, on the contrary, the amount 
of such associated mineral substance is generally small, and most of the 
graphite can be brought to a state of sufficient purity by hand-cobbing. 
The genetic relation of these pockety graphite bodies to the associated 
rocks has not been definitely decided, but they appear to have been formed 
along the contact of certain types of intrusive rocks with crystalline lime- 
stone or calcareous gneiss. The graphite of this type of deposit is of similar 
character to the foliated graphite of the veins, and where free from acces- 
sory minerals is of an equal degree' of purity. Fibrous or columnar graphite 
is not commonly present in such deposits, but may occur in small veins 
or off-shoots traversing the rocks in immediate proximity to them. There 
can be no doubt that both the above types of deposits are of epigenetic 
character and owe their origin to the igneous rocks with which they are 
associated. The graphite has probably been deposited by some sort of 
pneumatolytic action connected with the intrusion of these rocks, either 
on pre-existent fractures or on fissures caused by the fracturing of the 
invaded rock by the intrusive. 

Various theories have been advanced for the source of the graphite 
of such deposits. Weinschenk, who has made an exhaustive study of 
graphite deposits, favours the view that cyanogen compounds accompanied 
the intrusions and suffered a reduction to graphitic carbon. An alter- 
native theory regards carbon dioxide or monoxide gases as the substance 
reduced. In both cases, the source of the graphite is sought in the igneous 
rocks with which the deposits are associated. A third hypothesis suggests 
that graphite was formed at the expense of the invaded limestones, 
calcium carbonate being dissolved to form lime silicates and the liberated 
carbon dioxide reduced to graphite in the presence of hydrogen. The 
latter view calls for the presence of limestones in the more or less immediate 
vicinity of the graphite bodies, and it is noteworthy that this condition is 
observed in almost all instances where the geological relations of such 
crystalline graphite deposits have been studied in detail. In cases where 
the presence of limestones is not conspicuous, such rocks may yet be 
found to occur in depth. 

In place of limestone, other carbonate rocks, such as dolomite or 
magnesite, may conceivably have yielded the carbon dioxide. The Mun- 

1 See G. S. Bastin, Mineral Resources of the United States, Part II, 1913, p. 210. 



11 

glinup flake graphite deposits, Western Australia 1 , are associated with 
magnesite, and those of Eyre's peninsula, South Australia 2 , with magnesite 
and limonite. 

The necessary carbonate of lime may, also, have been furnished by 
the gneisses or schists; that they were originally more or less calcareous 
is evidenced by the frequent presence in them of garnet and other lime 
silicates. 

The theory that the graphite of such deposits has been formed at the 
expense of carbonate rocks is supported by the fact that the intrusives 
(usually pegmatitic in character) do not carry graphite as a component 
mineral. Graphite is often found in them in local aggregates of flake in 
the immediate contact zone, and also sometimes within the intrusive 
mass proper. Such graphite may, however, very possibly have been 
derived from limestone that has undergone solution by the igneous rock. 

In the case of the Canadian deposits, the ore-bodies are directly asso- 
ciated with intrusive rocks of a pegmatitic character. These, while usually 
of dike form, may also occur as bosses or laccolithic masses: the region has 
suffered so much deformation that their true form is often obscure. The 
graphite bodies appear to be associated in particular with rock of a gabbro 
or anorthosite type, or with modified forms of such rocks. Pegmatites 
of more acid character are abundantly developed throughout the region, 
but no graphite ore-bodies are associated with them. The fact that the 
graphite deposits are confined to those pegmatites carrying lime- or lime- 
soda-feldspar may have significance. 

Graphite is often developed along joint planes and fractures in the 
pegmatites, and in some cases appears to be disseminated through a large 
part of the mass of such intrusives. 

The graphite veins often show clearly that the crystallization of the 
graphite has proceeded simultaneously from both walls, the comb structure 
being quite distinct. In some cases, one-half the vein consists of foliated 
graphite and the other of fibrous graphite. 

As to the source of the carbon of the disseminated flake graphite 
bodies, considerable difference of opinion exists, and not all deposits of 
this type are considered to have a common origin. According to the gener- 
ally held theories, such graphites may be of either organic or inorganic 
origin, and are considered to have been formed in one or other of the follow- 
ing ways: — 

1. Through the alteration of organic, carbonaceous matter present 
as an original constituent of sediments. The graphitization of the carbon- 
aceous matter may have been achieved by contact, dynamo or regional 
metamorphism of the containing rocks. In such case, the graphite may 
be found in the position originally occupied by the carbon, or the latter 
may, conceivably, have migrated and under favourable conditions become 
concentrated and crystallized out as graphite. Such a mode of origin 
would thus conform to that of the amorphous graphites, the latter, however, 
having suffered a less intense degree of metamorphism. That this theory 
may be the correct one in the case of many deposits is supported by the 
fact that cases are known where carbonaceous slates have had their amor- 
phous carbon converted to graphite in the immediate vicinity of intrusive 
contacts, the transition from graphite to amorphous carbon with increasing 
distance from the contact zone being distinctly traceable 3 . 

'Bull. No. 76, Geol. Surv., West. Australia, 1917, p. 9. 

2 Min. Review, No. 27, Dept. Mines, South Australia, 1918, p. 52. 

3 See Stutzer, Die Nicht-Erze, p. 78. 



12 

2. Through the impregnation by pneumatolytic action of the country 
rock (limestones or calcareous schists, gneisses, etc.,) bordering intrusive 
contacts. Such a mode of origin is analogous to that suggested for the 
contact-metamorphic bodies of crystalline graphite. In this case, however, 
it would be necessary to assume certain peculiar conditions of composition 
or structure in the invaded rock, tending to make it permeable to solutions 
of gases, with consequent precipitation of the graphite in flake form within 
the mass of the rock, rather than as solid bodies of graphite. 

3. Through the destruction of calcium carbonate originally present 
in the rocks invaded by pegmatites, the lime going to form various sili- 
cates and the graphite being deposited more or less in situ by reduction 
of the carbon dioxide liberated. 

In the case of 2 and 3 the graphite may, possibly, also have been formed 
at the expense of calcium-magnesium carbonate, the intruded rocks often 
being dolomitic rather than purely calcareous. 

Both these theories, however, seem difficult to apply in the case of 
the graphitic crystalline limestones, in which graphite flakes often occur 
more or less uniformly distributed for considerable distances from intru- 
sive contacts. It would be reasonable to expect a far larger concentration 
of graphite in the immediate contact zone than is actually found to be the 
case in many such deposits. 

For a more detailed discussion of the theories of the origin of graphite 
the reader is referred to the extensive literature on the subject. Many 
of the more important treatises and articles are listed in the bibliography 
given as an appendix to the chapter on graphite in Mineral Resources 
of the United States for 1914, Part II, pp. 167-174. 

A supplementary bibliography containing articles, etc., on graphite 
that have appeared since the publication of the above report is appended 
to the chapter on graphite in Mineral Resources of the United States, 1917. 
Part II, pp. 117-119. 

Two further reports dealing with graphite that have recently been 
published are: — 

Ailing, H. L., The Adirondack Graphite Deposits, New York State 
Museum Bulletin No. 199, 1918. 

Dub, G. D., Preparation of Crucible Graphite, U.S. Bureau of Mines, 
War Minerals Investigations Series, No. 3, December, 1918. 

Articles and reports dealing particularly with Canadian graphite 
are listed on pp. 195-6 of this report. 



13 



CHAPTER III. 



COMPOSITION AND ECONOMIC IMPORTANCE OF GRAPHITE 

ORES. 

Practically all natural graphites, whether amorphous, crystalline, or 
flake, contain a certain amount of impurities in the shape of admixed 
mineral substance, the proportion of such impurities being commonly 
greatest in the flake ores. Many of the latter are really crystalline schists, 
in which the graphite has been developed subsequent to the formation 
of the rock proper. In these ores, the usual impurities are mica, calcite, 
quartz, feldspar, sulphide of iron (pyrites and pyrrhotite) and various 
silicates of lime, magnesia and alumina; in short, the typical, commoner 
metamorphic minerals. Where pronounced weathering of such ores has 
taken place, many of the above minerals are not to be recognized in their 
original form, having been converted into clayey material. In such case, 
a considerable enrichment in graphite has doubtless often resulted, due to 
the leaching out of the more soluble mineral constituents. 

In the case of the fresh, unaltered flake ores of the above type, such, 
for example, as those of the Canadian deposits, the common range of graph- 
ite content is from 10 to 30 per cent. The soft, decomposed ore of the 
Passau district, in Bavaria, on the other hand, commonly runs from 30 to 
50 per cent graphite. It is of gneissic type, somewhat resembling that of 
the Grenville series in Canada, but has suffered an intense degree of decom- 
position, the feldspar being mostly kaolinized. 

The crystalline graphites, such as that from Ceylon, are the purest 
of all natural graphites. They occur in vein form, and the amount of 
included foreign mineral substance is usually small, so that hand picking 
of the ore commonly suffices to prepare them for the market. Calcite 
and quartz are the principal impurities in such graphites, and the carbon 
content of the crude ore is from 60 to 70 per cent. By hand picking and 
cobbing, the impurities in many of such ores can be readily eliminated 
and a product running well over 90 per cent secured, while selected material 
may run over 99 per cent carbon. In the case of the columnar or fibrous 
ores, quartz sometimes forms a thin film or crust between the fibres, and 
is then more difficult to remove by hand. 

The amorphous graphites, in many cases, are the result of the metamor- 
phism of coal seams, whose carbon content has been converted into the 
graphitic form. The purity of such graphites naturally is dependent' 
on that of the original coal. Some are of high grade, as, for example, 
the Sonora (Mexico) graphite, which averages 86 per cent graphitic carbon, 
while those derived from coals high in ash are of correspondingly poorer 
quality. 

The low grade, amorphous graphite found near Providence, Rhode 
Island, occurs in the zones of more intensive metamorphism (apparently 
dynamic) of the coal, and appears to have been formed principally in the 
neighbourhood of anticlinal folds. The occurrence is a peculiar one, in 
that the beds at one point yield graphite, while not far away they have 
been worked for fuel. 

Amorphous graphite is also found finely disseminated in slates and 
shales. Such graphitic slates are, as a rule, relatively low in carbon, 



14 

and in most cases it is not practicable to refine the graphite, the ore being 
hand picked and ground up for use in paints, foundry facings, etc. 

With regard to the potential economic importance of graphite ores 
of the various types, it is difficult to generalize, since it is not merely the 
carbon content alone of a graphite that determines its value. Its physical 
form, relative refractoriness, and, in the case of flake graphites, the size 
of the flake, all are of paramount importance. The crystalline graphites 
(plumbago) and the flake form command the highest price. Crystalline 
graphite occurs in the form of veins, which are usually narrow and both 
difficult and expensive to work. Practically the whole of the world's 
supply of such graphite is derived from Ceylon, where cheap native labour 
renders possible the exploitation of the deposits. The cost of working 
such ore-bodies with white labour would almost certainly prove prohibitive, 
without a very material increase in the selling price. Such an increase 
would, however, react to the advantage of flake graphite, since it would 
probably result in the more extended use of the latter in crucible work, 
for which, as shown by recent investigations, this form of graphite may be 
emplo3 r ed without any serious disadvantage. 

While occurrences of crystalline graphite, approximately similar to 
that of the Ceylon deposits, are not uncommon in the Buckingham district, 
in Quebec, the narrowness and impersistence of the veins have prevented 
their exploitation, and there does not appear to be any likelihood that such 
deposits can ever be worked profitably. 

The governing factors in the case of disseminated flake ores are chiefly 
size of flake and a satisfactory milling and refining process to free the flake 
from the gangue and eliminate the impurities. The percentage of graphite 
in the ore is of somewhat lesser importance, since ores running as low as 
3 per cent have been successfully treated in the Alabama mills. The 
average of the ore treated in Canadian mills is 7 to 12 per cent. In the 
former case, however, the ore-bodies are very large and the ore is of more 
or less uniform grade, while in the latter, lenses or bands of richer ore merge 
into poorer material that has not been considered worth milling. 

The proportion of flake of larger than 90 mesh in the ore, and the 
employment of a milling process that will preserve the maximum amount 
of such flake from destruction as it passes through the various stages of 
concentration and refining, are also important, since it is only the larger 
flake that commands a price commensurate with profitable operation. 
Some flake graphite ores, while rich enough to be paying ores in themselves, 
are so hard that it is difficult to free the flake and at the same time preserve 
its size. Many of the graphite-gneisses may be included in this category, 
and often only the upper, weathered portions of such ore-bodies can be 
treated satisfactorily. In the case of both the Pickering graphite-gneiss, 
in Pennsylvania, and the Talladega slates (schists), in Alabama, the former 
carrying 5 per cent and the latter 3 per cent of graphite, operations are 
confined almost exclusively to the weathered rock above ground-water 
level. These ores require only the action of a muller-pan, or chaser-mill, 
to break them down sufficiently for concentrating. 

Amorphous graphites seldom possess a high graphitic carbon content, 
though a notable exception are the altered coal beds of Sonora, Mexico, 
which yield a high grade graphite that is in especial demand for lead pencil 
manufacture. Amorphous graphite is not uncommon in slates and shales, 
and such graphitic sediments have been worked quite extensively in cases 
where *he carbon content is sufficiently high. Low grade material, how- 



15 

ever, is only suitable for the cheaper qualities of commercial graphite, such 
as enter into foundry facings and paints, since, owing to the fine state of 
division of the graphite and the difficulty of separating it from its earthy 
matrix, it cannot be refined successfully. The cost of refining this class 
of material would be prohibitive, especially as the demand for pure, natural, 
amorphous graphite is limited; and apart from pencil manufacture, there 
are few, if any, industries employing graphite, to which it is essential as 
possessing properties not possessed by either the crystalline or artificial 
varieties. 

The increasing production of artificial graphite (5785 short tons in 
1917) 1 , its high degree of purity, low price and general suitability for many 
of the uses to which the natural amorphous is put, rather tend to reduce 
the general economic importance of deposits of the latter. 

It is difficult, unfortunately, to ascertain whether the composition 
of graphites as quoted in the various reports, etc., consulted, refers to 
the ores or to the graphite after milling and refining, and in many cases, 
tables would appear to include both without proper differentiation. Hence 
it is useless for comparative purposes to tabulate these analyses. G. C. 
Hoffmann, 2 however, has determined the composition of a number of 
Canadian ores, and the results of his analyses are appended: — 

Disseminated Flake. 



Locality. 


Carbon. 


Ash. 


Water. 


Total. 


Buckingham, Quebec 


27-52 
23-80 
22-38 
30-52 


72-44 
75-02 
75-88 
69-35 


004 
1-18 
1-74 
013 


100-00 
100-00 


u 


100-00 


« 


100-00 






Vein Graphite — foliated. 


Locality . 


Carbon. 


Asb, 


Volatile. 


Total. 


Buckingham, Quebec 

Grenville, Quebec 


99-68 
99-82 


0-14 
007 


0-18 
0-11 


100-00 
100- 00 


Vein Graphite — columnar. 


Locality. 


Carbon . 


Ash. 


Volatile. 


Total. 


Buckingham, Quebec 

Grenville, Quebec 


97-63 
99-76 


1-78 
13 


0-59 
0-11 


100-00 
100 00 



The flake samples were of the average ore from different deposits, 
while the vein material was selected for its purity. In the case of the 
flake, the proportion of rock matter soluble (calcite) and insoluble in hydro- 
chloric acid ranged from 2:66 to 21:53. 

1 Output of the Acheson Graphite Company, Niagara Falls and Buffalo. 

2 Geol. Surv. Can., Rep. Prog., 1876-7, p. 492. 



16 



Hoffmann also conducted analyses of Ceylon and Ticonderoga (New 
York) graphites, the samples in all cases being selected material : — 



Vein Graphite — columnar. 



Locality. 


Carbon. 


Ash. 


Volatile. 


Total. 




99-79 
98-82 


0-05 
0-28 


0-16 
0-90 


100-00 




100-00 










Vein Graphite — foliated. 








Locality. 


Carbon. 


Ash. 


Volatile. 


Total. 




99-68 
99-28 
96-66 
97-42 


0-21 
0-42 
2-15 
1-76 


011 
0-50 
1-19 
0-82 


100-00 




100-00 


Ticonderoga, N.Y 


100-00 
100-00 







Summary. — The crystalline, vein graphites are the purest natural 
graphites known, and can usually be turned into marketable material 
simply by a process of hand sorting. The veins, however, in most capes, 
are narrow and cannot be worked profitably without extremely cheap 
labour. With few exceptions, the vein graphites heretofore found on 
this continent have proved to be of little economic value on this account. 
Even with the supply of Ceylon plumbago shut off, these deposits would 
offer few possibilities, since the available tonnage would be small, and the 
expense of production probably too great to enable the material to compete 
with the flake graphites. The latter, while not as refractory as the more 
massively crystalline plumbago, could, if the necessity arose, be substituted 
for the latter in crucibles. Columnar graphite from Buckingham, Que., 
is illustrated in Plate III. 

The principal part of the world's production of graphite is made up 
of amorphous material. In 1913, the latest year for which more or less 
complete figures are available, the output of amorphous graphite amounted 
to over 80,000 tons, as against about 30,000 tons of plumbago and the 
same amount of flake. The greater part of the flake may be assumed to 
represent graphite that 'has undergone some sort of refining process, and 
has been derived from ores carrying from 3 per cent graphite upwards. 
Since in 1916, the production of Madagascar flake had risen to 28,000 tons, 
or more than 20,000 tons in excess of the 1913 output, while the Ceylon 
shipments had only increased 9,000 tons in the same period, the proportion 
of flake to plumbago in the total supply for 1916 was probably far greater 
than in 1913. No figures -are available since 1913 for the outputs of Ger- 
many and Austria; these countries in that year produced almost as much 
graphite as the rest of the world put together, and it may be assumed that 
the production in the interim has increased rather than diminished, owing 
to the shutting off of Ceylon imports. 

Transportation, fuel and other factors, of course, play an important 
role in governing the economic possibilities of graphite, as of other ore 
deposits. Commercial flake graphite ores, however, may be said to range 
all the way from 3 per cent carbon content upward, although the former 
are of exceptionally low grade, and can only be regarded as of possible 
economic importance in the case of large ore-bodies. The average graphite 



17 

content of the ores worked in Canada is 10 to 15 per cent, which is consider- 
ably higher than that of most of the deposits in the United States. The 
economic importance of a flake graphite deposit is in very large degree 
dependent on a cheap and efficient concentrating process. Should oil 
flotation prove the solution of the difficulty which has long embarrassed 
the flake graphite industry in this country, large quantities of material 
hitherto considered of too low grade to work will be converted into milling 
ore. 



18 



CHAPTER IV. 

GRAPHITE IN CANADA. 
Introductory Remarks. 



The graphite occurrences in Canada that have hitherto received any 
measure of attention lie in the eastern portion of the country. The dissemi- 
nated flake deposits are found in the Provinces of Ontario and Quebec, 
and within a radius of 150 miles of Ottawa. The Canadian graphite 
industry at its inception (1866-70) centered in the more or less immediate 
vicinity of Buckingham, Que., about 25 miles east of Ottawa, but the 
earlier mills in this district have long been out of operation. In recent 
years, some half dozen mills have been in more or less intermittent operation 
in the Buckingham area, all engaged in the production of flake graphite. 
Crystalline graphite, or plumbago 1 , also occurs in this region, but the veins, 
as a general thing, have been regarded as too narrow for profitable develop- 
ment. In more recent years,/ several flake graphite properties have been 
exploited in Ontario, in the region lying immediately to the west of Ottawa, 
and five mills have been erected in this section. Little, if any, crystalline 
graphite has been reported to occur in this district, the graphite all being 
of the flake variety. The occurrence on concession I, township of Brougham, 
in Renfrew county, (Black-Donald mine), of a mass of high grade flake ore 
is noteworthy, since such a graphite body is probably unique among known 
graphite deposits. The ore consists of rather small flake, the greater part 
of which is too small for the requirements of the crucible trade, but contain- 
ing local streaks of larger flake. The richness of the ore varies from 60 to 
80 per cent graphitic carbon, and the ore-body, which dips approximately 
vertically and is enclosed in crystalline limestone, has an average width 
of about 40 feet. 

Flake graphite has also been reported from several points in British 
Columbia, but none of the occurrences have been worked. Crystalline 
graphite has been found at various localities in the Northwest Territories 
and Labrador, and a deposit of this material was worked during 1917 and 
1918 on the south side of Baffin island. A small tonnage was secured 
during these operations and shipped to the crucible trade. The material 
is reported to be equal to the best Ceylon plumbago for this class of work. 

Amorphous graphite was worked a number of years ago near St. John, 
New Brunswick. The ore here consists of impure, graphitic shales and 
slates, and the material found employment in foundry facings and paint 
stock. 

The number of graphite mines and mills in operation during the last 
few years has averaged about half a dozen; in addition to which there 
has been intermittent work on a few deposits which, for one reason or 
another, have not reached the producing stage. 

The average annual production of graphite of all grades for the nine 
years 1910-1918 was 2,438 tons, this quantity comprising chiefly milled 
graphite; in certain years, however, a small tonnage of crude ore is included 
in the total. 



1 Note:— In this report the terms " crystalline graphite ", "vein graphite" and "plumbago" 
are used synonymously. While flake graphite also is essentially crystalline in character, it is 
not commonly so alluded to by the trade. 



Types of Deposits. 

The two predominant modes of occurrence of the disseminated flake 
graphite are (1) in more or less irregular bodies in sillimanite gneiss and 
(2) in crystalline limestone. Several ore-bodies of the latter type have 
been opened in Hastings and Haliburton counties, Ontario, but in Quebec, 
work has been, for the most part, confined to the graphitic bands in the 
gneisses. While it is clear that the latter type of deposit is the result of 
the graphitization of certain bands in the Grenville (sedimentary) series, 
this formation has suffeied such intensive deformation and metamorphism 
that the original continuity of the bands has been to a large extent destroyed, 
and they can seldom be traced for any great distance along the general line 
of their strike. Furthermore, the degree of graphitization and the shape 
of the ore-bodies would seem to bear a relation to local conditions of com- 
* position and structure, respectively, that prevailed in these rocks prior to 
their intrusion by the pegmatitic types, to the action of which the formation 
of the graphite would appear to be due. As a result, the ore-bodies are of 
somewhat irregular shape and extent, being in some instances saddle- 
shaped, as if they had formed at the crests of anticlinal or drag folds. In 
such cases, the formation of the graphite would seem to have been favoured 
by conditions of relief of pressure obtaining at such structural points. 

The ore-bodies are far from uniform in their graphite content, and 
are often characterized by zones of local enrichment. This may be due 
either to differences of composition or texture in the original rock, distance 
from the intrusive rock that caused the graphitization, or degree of influence 
that the latter has been able to exert. It is the zones of richer ore (10-20 
per cent) that constitute, for the most part, the ore-bodies that have hitherto 
been exploited. These, however, commonly grade into poorer ore that, 
while not capable of profitable treatment by the concentrating processes 
heretofore employed, may well be regarded as of considerable potential 
value for treatment by flotation. 

The graphite deposits in crystalline limestone commonly occur in 
immediate proximity to pegmatitic intrusions, the ore-bodies being in the 
silicated portions of the limestone along its contact with the intrusive. 
In some cases, the limestone rock has been in the nature of a relatively 
narrow calcareous band intercalated in gneisses, in which case the ore- 
body has more or less definite form. In other instances, pegmatites have 
been intruded into large limestone masses, with the formation of a graphitic 
zone varying in richness with distance from the contact. Since the peg- 
jnatites often have the form of laccoliths rather than well defined dikes, 
and since the entire complex appears to have suffered intensive deformation 
subsequent to the period of intrusi6n, the ore-bodies usually possess decidedly 
irregular form and the true relationship is often obscured, thus rendering 
the blocking out of an ore-body a difficult .task. In such cases, diamond 
drilling is the only reliable means of determining the general form and 
extent of the ore-body. 

- Another type of graphite deposit that is of less common occurrence, 
but of which several instances are known and have been exploited, is that 
in which both crystalline and flake graphite occur associated together. 
Such deposits are essentially contact-metamorphic in type, and are char- 
acterized by the intimate association of such minerals as wollastonite, 
scapolite, pyroxene, vesuvianite, garnet and sphene with the graphite, the 
whole forming a rather loose aggregate of coarsely crystalline individuals. 
The interstices are usually filled out with calcite. Except that it is prone 



20 

to be more impure, by reason of the occurrence through its mass of the 
above minerals in greater or lesser amount, much of the crystalline graphite 
from this type of deposit is essentially similar to the foliated graphite of 
the true veins. The former, however, is usually less lustrous, is often of 
a grey shade rather than black, and is softer and less compact, breaking up 
rather readily into fragments of flake form, as contrasted with the more 
angular particles yielded by vein plumbago. The graphite is evidently 
of contemporaneous origin with its associated minerals, being often con- 
spicuous within the larger individuals of scapolite, pyroxene, etc. These 
deposits, in their general character, closely resemble the mica-apatite 
bodies found in the same series of rocks in the Buckingham district, Que. 

Leaving out of consideration the amorphous variety, Canadian graphite 
thus occurs in deposits of three types, each essentially different in its general 
characteristics, though possibly alike genetically. The geology of the 
graphite-bearing areas in Ontario and Quebec has been studied in detail 
during the past few years by M. E. Wilson and J. Stansfield, of the Geolo- 
gical Survey, and for a discussion of the mode of occurrence and origin of 
the graphite bodies and their associated rocks the reader is referred to the 
articles in the footnote 1 . 

Briefly summarizing the salient points respecting the occurrence and 
origin of the graphite deposits, it may be stated that three hypotheses 
have been proposed to explain the mode of origin of graphite. These 
hypotheses attribute the source of the graphite to: — 

(1) Carbon, of organic origin, originally present in sedimentary rocks, 
which latter have been metamorphosed by dynamic- or contact-meta- 
morphism (or a combination of both), with conversion of the carbonaceous 
material to graphite. 

(2) Deposition by pneumatolytic agency, the graphite having been 
introduced into rocks immediately adjacent to igneous intrusions. In 
this case, the source of the graphite is ascribed either to cyanogen or hydro- 
carbon compounds originally present in the igneous magma or to carbon 
dioxide accompanying the intrusive. 

(3) Reduction of the carbon dioxide derived from the breaking down 
of the calcium carbonate of rocks (limestones, calcareous schists and 
gneisses, etc.) by contact-metamorphic action along the borders of igneous 
masses (pegmatites) intrusive into such rocks. 

While the above hypotheses have been adduced to explain the origin 
of graphite deposits in general, one particular theory being proposed for 
one or other of the types of deposits mentioned above and not being 
regarded as necessaiily applicable to all types, the close association of all 
three classes of deposits in Canada within a comparatively limited area 
of rocks of essentially similar character (crystalline limestones and gneisses 
intruded extensively by pegmatite rocks of different periods and types, 
but all, alike, of Pre-Cambrian age) would suggest that the graphite has, 
in all cases, been derived from a similar source. 

While, of the three classes of deposits referred to, that of flake graphite 
disseminated in limestone or gneiss is the only one to which the theory of 
original carbon content can rationally be applied, there is little evidence 
to adduce in support of such a hypothesis. Against this theory, however, 
is the fact that although the entire system of limestones and gneisses 
(Grenville series) in which the graphite bodies occur has suffered a degree 

1 Trans. Can. Min. Inst., Vol. XVI, 1913, pp. 401-11; Vol. XIX, 1916, p. 362; Geol. Surv. Can., 
Summary Report, 1917, Part E, pp. 29-42. 



21 

of dynamic- and (locally) contact-metmorphism sufficient to bring about 
the formation within and throughout the mass of these rocks of many 
typically secondary minerals, such as mica, garnet, tremolite, wollastonite, 
pyroxene, etc., graphite ore-bodies seem to be confined to the immediate 
vicinity of bodies of intrusive rock, and probably of intrusive rock of a 
certain type, namely, one high in lime-soda (plagioclase) feldspars. It 
seems probable, therefore, that if an original carbon content of the Grenville 
series were the source of the graphite found in this series, graphite bodies 
would be of far more widespread occurrence throughout the mass of these 
rocks than is the case. 

Relatively little underground work has been done in connexion with 
the exploitation of graphite bodies, and small, surface excavations have 
largely had to suffice for a study of the relation of the deposits to their 
associated rocks. The general impression gained from an examination 
of the ore-bodies exposed in such surface workings is that the carbon of 
the rocks is of secondary rather than of primary origin, and that its form- 
ation is connected in some manner with intrusions of pegmatite rocks into 
the gneisses or limestones. Whether, however, the source of the graphite 
is to be sought in the intrusives themselves or is to be ascribed to reduction 
of the carbon dioxide liberated from the calcium carbonate of the invaded 
rocks is a matter of speculation. The latter question is perhaps not of 
such particular import with regard to the exploitation of graphite deposits. 
The establishing of a direct connexion between the occurrence of ore-bodies 
with intrusive rocks of a certain type would, however, be of decided interest 
and possibly, also, of material assistance in the development of deposits. 
In this connexion, also, the question of the influence of structure, and the 
possible tendency of graphite to accumulate at the crests of folds or at 
other points at which a relief of pressure occurred, should be taken into 
consideration. 1 

Mining Methods. 

There is little of particular interest to be recorded as to the method 
of working Canadian graphite deposits. The usual procedure has been 
to exploit the occurrences, both of the disseminated flake bodies and of 
the veins or contact zones of plumbago, by surface pits opened on the most 
promising outcrops, and to continuous sinking as long as the ore-body held 
out. Such pits have seldom been carried to any great depth, 100 feet 
being an extreme. Where the outcrop occurs in the face of a declivity, an 
open cut is started on the level ground at the foot and a drift carried into 
the face. If the ore-body warrants it, stoping of the ore is conducted from 
this drift, but underground workings of such nature are seldom extensive. 
Most of the workings in the Buckingham district consist of rather shallow 
open pits, of which there are often a considerable number on the one 
property. The entire complex of crystalline rocks in which the graphite 
bodies occur has suffered such an intense degree of deformation that any 
systematic development along the lines of blocking out ore is usually out 
of the question, and exploitation of the deposits resolves itself into the 
most economical method of extracting the ore in sight with the removal 
of the least amount of dead rock. 

At only three mines has any extensive underground work taken place. 
At these mines, a more than usually well defined ore-body has been exploited 

1 See Geol. Surv. Can., Summary Report, 1917, Part E, p, 40, 



22 

by means of shafts respectively 125, 200, and 250 feet deep, with levels 
from which stoping of the ore has been carried out. In two cases, the 
shaft is inclined, and in the third, vertical. 

The rock enclosing the graphite bodies is usually tight and little 
timbering of the workings is required. 

Hoisting is performed in the case of the shallow open pits by bucket 
and derrick, and at the deeper mines on skip ways. 

Most of the mines situated at a distance from the railroad employ 
hardwood as fuel for boilers and drying kilns. 

Physiographic-ally, the graphite bearing region of Ontario and Quebec 
consists of low hills and ridges of crystalline rocks, the intervening valleys 
being largely occupied by areas of glacial drift. Numerous lakes occupy 
the major depressions, and are usually elongated in the direction of the 
prevailing strike of the rocks, which is northeast. The country is well 
wooded, with an abundance of second growth maple, birch, cedar, spruce, 
balsam, etc. 

GRAPHITE MINES AND OCCURRENCES. 

PROVINCE OF BRITISH COLUMBIA. 

There is no recorded production of graphite from this Province, and 
no references to the presence of the mineral is contained in the reports of 
the Provincial Mineralogist. Several occurrences of the mineral are 
known, however, the principal being the following: — 

Alkow harbour, Dean channel, Bella Coola mining district: Graphite 
was recorded from this locality as far back as 1860. The graphite occurs 
in minute flakes, associated with pyrites, in a matrix of heulandite. A 
sample of the material, analysed in the laboratory of the Geological Survey, 
contained 23 per cent of graphite. (G.S.C. Ann. Rep., Vol. IX, 1896, p. 
16R.) 

Matthew creek, Marysville, Fort Steele mining district: An occurrence of 
graphite at this point was examined by the writer in 1916, and is described 
in the Mines Branch Summary Report for that year, p. 34. The graphite 
is amorphous and occurs disseminated in a matrix of earthy silicates. The 
occurrence appears to be a vein formed at the contact of a dioritic rock 
with mica schist. The graphite content of a selected sample was found 
to be 25 per cent. The maximum width of the deposit, as exposed in a 
small surface cut, is 2 feet. The low graphite content of the ore and the 
narrowness of the vein do not indicate that the deposit possesses any 
economic value. 

Harrison lake, New Westminster mining district: According to a commu- 
nication received from W. A. Blair, of the Vancouver Board of Trade, 
graphite occurs in the above district, and two carloads of ore were shipped 
from the deposit some years ago. Nothing further is known of this 
occurrence. 

PROVINCE OF NEW BRUNSWICK. 

New Brunswick in the past has produced consideiable quantities of 
amorphous graphite, which is found in bedded deposits in limestone at 
several localities, but hitherto in commercial quantities only near St. John. 
The workings at this locality were at Split rock and Marble cove, near the 
suspension bridge over the St. John river, Lancaster parish, St. John 
county. The earliest work here appears to have taken place in 1853, the 



23 

initial production being 45 tons* of crude ore. After lying idle for some 
years, the workings were re-opened in 1868 and produced an average of 
about 1000 tons of crushed and screened graphite for several years. The 
deposits were worked intermittently, either at the original locality or in 
its more or less immediate vicinity, for a number of years, most of the 
output finding employment in foundry facings. The price secured for 
the crude material in 1890 was $7 per ton f.o.b. cars, and most of the 
output .went to the United States. An annual production ranging from 
100 to 400 tons is recorded for the years 1885-88. 

In 1892, Ingall reports that a certain amount of ore was being ground 
and cleaned in a mill erected on the property. In 1895, the Canada Paint 
Company, of Montreal, commenced to operate the deposits, their workings 
being at Marble cove, and from this year until 1908 took out about 100 
tons of graphite annually. This material was shipped to the Company's 
paint works at Montreal. Since 1908, no further work has been conducted 
at this or any other graphite locality in the Province. 

According to Bailey and Matthew, 1 the graphitic bands occur in 
argillites and sub-crystalline limestones, and vary from 1 to 4 feet in 
thickness. Graphite also occurs in a finely disseminated form throughout 
large areas of the limestones. 

According to Ingall 2 , the graphite occurs at the contact of crystalline 
limestone and a trap dike. The deposit on the Hazen property was worked 
by a drift run along the ore-body from the bottom of a 50-foot shaft. At 
30 feet, the deposit was found to be 10 feet thick. 

A sample of the ore from the old Split rock workings was analysed by 
G. C. Hoffmann 3 , of the Geological Survey, in 1878, and was found to contain 
49 per cent of graphitic carbon, 50 per cent of insoluble, and 1 per cent of 
water. The sample had a loose, shaly structure and contained a considerable 
amount of pyrites. 

This locality was visited by A. O. Hayes, in 1913, who gives 4 the 
following notes on the occurrence of the graphite: — 

"Graphite occurs on the northeast shore of the St. John river, at the 
falls. It may be seen outcropping at intervals from the shore a few hundred 
feet north of the railway bridge, northerly for about 500 yards along a 
small valley, to a point east of Murray and Gregory's sawmill. Near the 
sawmill, an old dump of considerable size has been taken from a shaft, 
and other old workings are found in the valley. A section across the occur- 
rence may be seen at its southern extremity near the river, where a small 
tunnel 20 feet long has been driven. 

"Here the graphite occurs in a vertical fault zone mixed with dark 
coloured pyritiferous shales much reddened with iron oxide. The country 
rock to the east of the fault zone is dark blue limestone and in order from 
east to west, the following section was measured. 

2 feet graphitic shale with calcite. 

3 " green shale somewhat graphitic. 
6 " shaly graphite. 

6 " green limestone. 

8 " hard graphitic shale. 

6 " green earthy rock which does not effervesce with acid." 

References : — 

Geol. Surv. Can., "-Report of Progress, 1870-1, p. 231; Report of 
Progress, 1876-7, p. 329; 3 Report of Progress, 1878-9, p. 3H; 2 Annual 

67945-3 



24 

Report, Vol. V, 1890-1, p. 71SS; Annual Report, Vol. VI, 1892-3, p. 63S; 
Annual Report, Vol. X, 1897, pp. 72-74M; Bulletin on Graphite, 1904, pp. 
6-10; 4 Summary Report, 1913, p. 242. 

Mines Branch, Monograph on Graphite, 1907, p. 50. 

Other localities in New Brunswick from which amorphous graphite 
has been recorded are: near Dumbarton station, on the St. Andrews 
branch of the Canadian Pacific railway; Thorn Brook, parish of Havelock, 
in Kings county; near Dorchester, in Westmorland county; Goose river, 
St. Martin's parish, St. John county; Lepreau harbour, in Charlotte 
county; and in the parishes of St. Stephen and St. Patrick, Charlotte 
county. 

The Lepreau harbour material somewhat resembles the well-known 
Rhode Island graphite, being a graphitic anthracite. The deposit was 
mined around 1880 for coal, and several shafts were sunk, one of which 
reached a depth of 140 feet. (G.S.C., Rep. Prog., 1878-9, p. 13D.) 

The Thorn Brook occurrence is described as a band of earthy graphite, 
20 feet wide, in jointed and broken slates. The deposit is said to have been 
traced for over a mile along its strike. (G.S.C., Ann. Rep., 1890-1, Vol.V, 
p. 71SS.) A sample of material from this deposit, analysed in the labora- 
tory of the Geological Survey, showed only 7-5 per cent of graphitic 
carbon. 

PROVINCE OF NOVA SCOTIA. 

There is no recorded production of graphite from Nova Scotia, though 
occurrences of amorphous material are recorded from various localities, 
most of them in Cape Breton. According to Ells 1 , several attempts to 
exploit graphite deposits have been made at different times, but without 
much success. The following notes on graphite occurrences in the Province 
are taken from the reference in the footnote. 

The deposits in Cape Breton island are found in rocks consisting of 
crystalline limestones, slates and shales, which are intruded by granitic 
types. The principal localities comprise the following: — 

Glendale, river Inhabitants, southern part of Inverness county; 
graphitic shale, carrying from 14 to 32 per cent of graphite, according to 
analyses made in the laboratory of the Geological Survey. An analysis of 
the shale from Christmas island, which is part of the same series, showed as 
high as 50 per cent of graphite. Graphite from this locality was awarded 
diplomas at the Paris and Glasgow exhibitions, in 1901. The syenite 
intruding the shales at Glendale carries graphite specks disseminated 
through it. At Dallas Brook, near West bay, graphitic limestones and 
shales were at one time mistaken for coal measures. 

Guthro lake, near Frenchvale, Boisdale hills, northern part of Cape 
Breton county: graphitic shale, carrying 38 to 45 per cent of graphite, and 
occurring in a band 2 to 3 feet wide. Some development work was done 
on this occurrence in 1895 2 . 

Other graphite localities on Cape Breton island include Boularderie 
island, Victoria county, and Gillis and Gregwa brooks, about the head of 
East bay, Cape Breton county. 

On the mainland, graphitic shales are reported to occur near Parrsboro, 
on Minas basin, Cumberland county, and in Guysborough county, on 
Salmon liver, flowing into Chedabucto bay. 

1 Geol. Surv. Can., Bulletin on Graphite, 1904, p. 5. 



25 

Graphite is also present in the slates of the Nova Scotia gold-bearing 
series, as at Musquodoboit, Fifteen-mile stream and Hammond plains, in 
Halifax county. 

References * — 

Geol. Surv.Can., Rep. Prog., 1878-9, p. 2H; Rep. Prog., 1879-80, pp. 
19 and 125F, and p. 1-2H; 2 Ann. Rep., 1896, Vol. IX, p. 52R; Bulletin 
on Graphite, 1904, pp. 5-6. 

Economic Minerals of Nova Scotia, Department of Public Works and 
Mines, Halifax, 1903, p. 22. 

Mines Branch, Monograph on Graphite, 1907, p. 52. 

Mineral Map of the Province of Nova Scotia, Department of Mines, 
Halifax, 1912. 

PROVINCE OF ONTARIO. 

The earliest mining and milling of graphite in Ontario took place in 
1870, in which year the Port Elmsley deposit was opened up and a refining 
plant erected at Oliver's Ferry, on the Rideau canal. This mine remained 
the sole producer until 1896, when operations were commenced at the 
famous Black Donald mine, in Renfrew county. This deposit is unique 
among known occurrences of flake graphite, both on account of its size and 
the phenomenal richness of its ore. The latter runs so high in graphite 
that a considerable tonnage is shipped crude for employment in certain 
industries. 

The Black Donald mine has continued practically unbroken opera- 
tions since 1896 to the present time, and probably has produced more 
graphite than all other Canadian mines together. 

The graphite deposits of Ontario occur associated with crystalline 
limestones, rather than with gneiss, as is the more general mode of occur- 
rence in Quebec, and all of the five mines in the Province have limestone 
as the rock enclosing the ore-body. 

The following table shows the production of graphite in Ontario from 
1896 to 1918:— 

Production of Graphite in the Province of Ontario, 1896 to 1918. * 



Year. 


Short tons. 


$ 


Year. 


Short tons. 


$ 


1896 


650 

400 

300 

1,220 

1,802 

1,000 

. 1,923 

4,400 

355 

152 

1,772 

2,000 


13,000 

8,500 

6,000 

16,179 

27,030 

20,000 

17,868 

20,636 

4,700 

9,825 

15,000 

20,000 


1908 


10 

730 
992 
894 
1,246 
1,788 
1,363 
2,534 
3,446 
3,173 
2,934 


1,600 


1897 


1909 

1910 


37,624 


1898 


55,637 


1899 


1911 

1912 


36,492 


1900 


65,076 


1901 


1913 

1914 


93,054 


1902 


87,167 


1903 


1915.. . 


115,274 


1904 

1905 

1906 


1916 

1917 

1918 


249,586 
296,587 
171,227 


1907 











Descriptions of the graphite mines in the Province are given in the 
following pages. 



1 Compiled from Annual Eeports of the Ontario Bureau of Mines. 
67945—3| 



26 

FRONTENAC COUNTY. 
Township of Bedford. 

Concession IV, lot Jj., and concession V, lot 4. — These lots are understood 
to have been recently taken up by the Mining Corporation of Canada, 
1511 Bank of Hamilton Building, Toronto, with a view to their develop- 
ment. 

Concession VI, lot 2. — According to a statement by J. Bawden, 1 a 
30-foot shaft was sunk on this lot some years previous to 1890, and about 
100 barrels of crystalline graphite were taken out and shipped to the United 
States. The occurrence is described as " a well defined vein fully three- 
quarters of a mile in length and 10 feet wide" in crystalline limestone. No 
further work appears to have been done on this deposit. 

HALIBURTON COUNTY. 
Township of Cardiff. 

Concession XXII, lots 9,10 and 11. — Owned by the National Graphite 
Company, .Royal Bank Building, Toronto. The property lies a few 
hundred yards south of the Irondale, Bancroft and Ottawa branch of the 
Canadian Northern railway, f of a mile west of Mumford station. It was 
taken up originally in 1912 by the New York Graphite Company, who 
erected a large mill and proceeded to develop an ore-body outcropping 
along the north slope of a low ridge facing the railway. A series of small 
pits opened along this ridge showed the presence of a rather flat-dipping 
ore-body having an easterly strike and dipping south. The deposit has 
been proved for a distance of several hundred feet, and several small drifts 
were run, from which a small tonnage of ore was secured. The largest 
opening is an open pit 40 feet deep, by 60 feet long and 15 feet wide. The 
deposit has also been tested by a number of diamond drill holes. The 
New York Graphite Company continued intermittent operations up to 
1915, when it was merged into the present Company. Mining was thence- 
forth largely discontinued on the above lots, and ore was shipped to the 
mill from a deposit in Hastings county, near Maynooth. 

The latter property is situated on lot 24, concession XIII, township 
of Monteagle, and adjoins that of the Tonkin-Dupont Graphite Company. 
The ore is essentially similar to that found on the adjoining lot (see page 28), 
and consists of crystalline limestone, mixed with silicates, and carrying 
about 7 per cent of large sized, lustrous flake graphite. An appreciable 
amount of molybdenite was noticed on the waste dump. A considerable 
quantity of ore was taken off this lot during 1915 and 1916, but neither 
mine nor mill have been producing actively since early in 1917. At the 
present time it is understood that re-opening of the mine at Mumford is 
contemplated. Experiments are being made, also, with a new system of 
flotation concentration. 

The workings in Monteagle township comprise one main pit and two 
smaller openings, the latter 50 feet and 20 feet deep respectively. The 
main pit is an irregular shaped opening, measuring 150 X 30 feet and 150 
feet deep, following an ore-body with a northwesterly trend and a slight 
dip to the southwest. This pit is cribbed and timbered for part of the way, 
and is equipped with a skidway for bucket hoisting. The openings, being 

1 Report of the Royal Commission on the Mineral Resources of Ontario, 1890, p. 52. 



CANADA 

DEPARTMENT OF MINES 

MINES BRANCH 

riN Borrell, Minister. R.G.MT Connell . Deputy Mini 
Eugene Haanel. Ph.D.. Di 




Base map, Dept. of Interior 



GRAPHITE OCCURRENCES 



BEDFORD, LOUGHBOROUGH, BURGESS, N. AND S. 
AND ELMSLEY N. Tps., ONTARIO 

Scale; 3 95 miles to one Inch 

Reference 

1 N. A. Timmins 

2 Globe Graphite Mining and Refining Co. 
(•) Mine equipped with mill 

% Mine 
U Mill 
O Undeveloped prospect 



' ■ - • ■ '■-•:-- , - 



CANADA 

DEPARTMENT OF MINES 

MINES BRANCH 

TIN BuRRELL. MINISTER. R . G. M? CON N E LL . DEPUTY I 

Eugene Haanel. Ph.D.. Director. 



78°I5' 




Base map, Dept. of Interior 



GRAPHITE OCCURRENCES 



MONMOUTH, CARDIFF, MONTEAGLE AND DUNGANNON Tps., ONTARIO 

Scale; 3-95 miles to one inch 

Reference 

1 National Graphite Co. 

2 Tonkin-Dupont Graphite Co. 
® Mine equipped -with mill 

• Mine 

O Undeveloped prospect. 



to 
15 

mi 

30 
10 
St 
qi 
fu 



27 

situated on high ground, make little water. There is a steam plant and 
compressor at the mine, and in addition, a similar installation at Graphite 
siding on the railway. . The latter was put in in 1916, but has never been 
in operation. 

The Company's mill at Mumford is a large, 3-story, wooden building, 
designed to treat 200 tons of ore per 24 hours. Steam is furnished by 
three 150 H. P. boilers, and one 250 H.P. engine drives the mill machinery 
and electric lighting plant. An inclined tramway (see Plate VI) conveys 
the ore from the dump alongside the spur connecting the mill with the 
railway, to a tipple, where it is dumped into cars that take it to the drying 
kilns. The latter are oil-fired. The system of concentrating and refining 
is dry throughout, and in a general way similar to that described on pages 
74-8. Two Huff electrostatic separators were installed in 1916. It was 
claimed that the No. 1 product turned out by this mill had an average 
carbon content of 92 per cent, while the No. 2 ran around 90 per cent. 
The output of milled graphite in 1916 was 900,000 pounds. 1 

References — 

Annual Reports of the Ontario Bureau of Mines, 1913 to date. 

Township of Monmouth. 

Concession XVI, lot 35, S J-. — Owned by the Tonkin-Dupont Graphite 
Company, Ltd., 2345 Broadway, New York. The property adjoins the 
Irondale, Bancroft and Ottawa branch of the Canadian Northern railway, 
near Wilberforce station. A large mill, erected by the original owners, the 
Virginia Graphite Company, in 1910, is situated alongside the railway 
tracks, close to the station. 

The first work at this point was carried out in 1910 by the last mention- 
ed Company, who proceeded simultaneously with the erection of the mill. 
A small amount of mining was performed on the above and adjoining lots, 
but results apparently were not very promising, as in the following year 
the mill ran largely on ore brought by rail from Maynooth, some 30 miles 
away, where, on concession XIII, lot 23, of the township of Monteagle, in 
Hastings county, the Company carried out more extensive mining opera- 
tions. The workings at Wilberforce comprise a few small side hill quarry 
openings, a large open pit said to be about 100 feet deep and measuring 
75 feet X 40 feet, and an inclined drift 8 feet X 15 feet and 100 feet deep. 
The latter opening has been made on a graphitic, zone in silicated crystal- 
line limestone, the graphite occurring in narrow bands of disseminated 
flake, separated by limestone only slightly graphitic. The prevailing rock 
on these lots is crystalline limestone, in which occur silicated bands. It 
is to these bands that the graphite is confined. The ore is comparatively 
low grade, probably averaging about 5 per cent of graphite. A cursory 
examination of these lots did not reveal any indication of the presence of 
an important ore-body. 

In 1913, the name of the Company was changed to the Tonkin-Dupont 
Graphite Company. Some prospecting by drill was carried out on the 
Wilberforce property during the year, but most of the ore milled was brought 
from Maynooth and from several prospects in Monmouth and Cardiff 
townships. Since 1913, the mines and mill of the Company have been 
idle. 

The mill at Wilberforce is a large, 3-story building (see Plate VII), and 
is equipped with dry concentrating machinery. The kilns for drying the 

1 This mill has since been remodelled for flotation concentration. 



28 

ore are situated on a ridge back of the mill, being fed by a skipway leading 
from the ore dump situated alongside the railway siding which runs to the 
mill. The concentrating process was modelled on the lines described on 
pages 74-8, the concentrates being refined by Huff electrostatic separators. 
The mill was designed for a capacity of 200 tons of ore per 24 hours. Steam 
was supplied by two 125 H.P. boilers. 

The workings of the Company on lot 23, concession XIII, township 
of Monteagle, in Hastings county, comprise one main pit 200 feet long by 
20 feet wide and 75 feet deep, and several other smaller openings to the 
southeast of the above. The large pit yielded most of the ore taken off 
the property. The ore-body worked consists of a graphitic band in crys- 
talline limestone, having a northwesterly trend and dipping slightly to the 
southwest. It is a continuation of the same band worked on the adjoining- 
lot (XIII, 24) by the National Graphite Company. 

The ore consists of large-sized, lustrous graphite flakes, disseminated 
in silicated, crystalline limestone, the average graphite content being about 
7 per cent. Calcite forms the bulk of the impurities in the ore, with mica 
and pyrrhotite in subsidiary amount. The ore-body is bordered by zones 
of silicated limestone, of which diopside, tremolite, mica, garnet, apatite, 
pyrrhotite, sphene, scapolite and other typical contact-metamorphic 
minerals are the most conspicuous components. The occurrence of small, 
clear, lustrous prisms of scapolite is of mineralogical interest. 

The mine is equipped with a small steam plant, compressor and hoist. 
The ore was hauled to a siding at Graphite, on the Central Ontario railway, 
about 1 mile distant, and shipped via Bancroft to the Company's mill at 
Wilberforce. 

References — 

Annual Reports of the Ontario Bureau of Mines, 1912-15. 

LANAKK COUNTY. 
Township of North Burgess. 

Concession V, lots 24, 25 and 26. — Owned by N. A. Timmins, Canadian 
Express Building, Montreal. Development of this property commenced 
in 1918, and a mill is now in course of erection. 

The graphite occurs as disseminated flake in a band of silicated 
limestone, the graphite content being about 7 per cent. The width of 
the graphitic zone as exposed in the main pit is 12 feet. Ore is being- 
mined open-cast at the present time on lot 24, at a point about 700 yards 
east of the mill, where the graphite body outcrops on the south side of a 
small hill. When the mine was visited early in 1919, this pit was 75 feet 
long and 20 feet deep. 

The property was diamond drilled in 1918, six holes being put down 
to depths ranging from 90 to 200 feet. These holes are reported to have 
shown the presence of a large tonnage of ore that will assay 5-7 per cent 
carbon. The graphitic band has been traced on the surface and proved 
by drilling for a distance of f mile. The chief impurities in the surface 
ore are calcite, pyroxene, mica and iron sulphides. 

The mill is being equipped for film notation by a newly patented 
system. The equipment consists of Gates gyratory crusher, ball mill, 
notation washers, rotary dryer, burrstones and polishing rolls. A pipe 
line 5,000 feet long has been constructed between the mill and Black lake, 
and it is planned to connect the pit and mill by tramway. 



29 

The mine lies 14 miles southwest of Perth, and 7 miles from Westport, 
the nearest rail point. 

Township of North Elmsley. 

Concession VI, lots 21 and 22. — Property of the Globe Graphite 
Mining and Refining Company, of Syracuse, N.Y. This property lies 
7 miles southeast of the town of Perth, and 4 miles from Elmsley station 
on the Montreal-Toronto line of the Canadian Pacific railway. The 
distance to Rideau lake is less than 1 mile, and from here shipments may 
be made or received by way of the Rideau canal connecting Ottawa with 
Kingston, on Lake Ontario. 

Work on this deposit — the earliest worked graphite occurrence in the 
Province — was commenced about 1870, by the International Mining 
Company, of New York, and continued until 1875, the ore being hauled 
to a mill erected at Oliver's Ferry, on the Rideau canal. From 1875 to 
1893, the property was idle. In the latter year it was taken over b}^ the 
Northern Graphite Company, who put down boreholes on lots 21 and 22 
in concession VI, and on lot 23 in concession VII. Eight holes were 
put down, ranging from 50 to 100 feet in depth, and a considerable 
body of graphite was proved. No active mining was conducted by the 
above Company, and the property lay idle until 1901, when it was again 
drilled, by R. A. Pyne, who put down four diamond drill holes on lot 21. 
The holes ranged from 64 to 140 feet. In 1902, mining was commenced 
by Rinaldo McConnell, who carried out considerable development work, 
put down seven diamond drill holes and established a 20-ton mill at Port 
Elmsley, 3 miles to the east of the mine. From 1903 to 1908, operations 
were again suspended, but the mine and mill were run almost continuously 
between 1908 and 1911 by the Globe Refining Company. From 1912 to 
1915 the property was idle, but in October of the latter year the Globe 
Graphite Mining and Refining Company was formed and work was 
resumed. The assets of this Company were taken over in 1916 by the 
present owners, who have continued to operate the mine and mill to date, 1 
and have carried out several hundred additional feet of diamond drilling. 

This property was examined in 1917 by M. E. Wilson, of the Geological 
Survey, and from his report 2 the following notes on the occurrence of the 
graphite are largely taken. 

The graphite ore-body, as disclosed by mining and drilling operations, 
forms a saddle-shaped mass in highly silicated Grenville limestone intruded 
by masses of pegmatitic rock. The latter ranges in composition from 
a gabbro to a syenite, and commonly contains pyroxene and biotite. 
The graphite is associated principally with silicated zones in the limestone, 
and the graphite content increases in proportion to the degree of silication. 
The silicated rock consists chiefly of diopside with subsidiary amounts 
of scapolite, mica, pyrite, and orthoclase feldspar, and apparently represents 
a contact-metamorphic product formed along the borders of the peg- 
matitic rocks. The silicated zones merge gradually into the normal 
Grenville limestone. 

In addition to the graphite being found in the more highly silicated 
portions of the limestone, the shape of the ore-body indicates a possible 
connexion between its formation and the structure of the enclosing lime- 
stone. In general form, the ore-body is an unsymmetrical, saddle-shaped 
mass — 40 feet thick at its crest — developed on the limbs of a pitching 

1 Went into liquidation in February, 1919. 

2 Geol. Surv. Can., Summary Report, 1917, Part E, pp. 29-42. 



30 




Fig. 1. Surface plan at mine of Globe Graphite Mining and Refining Company, 
lots 21>nd 22, concession VI, North Elmsley township, Lanark 
county, Ontario. 



31 

anticline; the saddle thus occupies a highly-tilted position, the axis of the 
anticline being horizontal rather than vertical (see Fig. 2). The general 
trend of the limestone is northeast, paralleling the longer direction of the 
pit, with a steep dip to the north. At the eastern end of the pit, however, 
the banding in the limestone turns abruptly to the south, forming an 
anticline pitching steeply to the northeast. The graphite body is developed 




Fig. 2. Diagram showing approximate form of graphite ore-body on crest of pitching 
anticline, lots 21 and 22, concession VI, North Elmsley township, Ontario. 

for a distance of 400 feet along the northwest limb of this anticline, gradually 
increasing in width from west to east, until at the crest it attains a thickness 
of 40 feet. 

With regard to the possible bearing of structural relationships in the 
Pre-Cambrian rocks on the formation of graphite bodies, Wilson says: — 

The outstanding structural feature which characterizes the graphite deposits 
occurring in the Pre-Cambrian complex of eastern Ontario and the southern Laurent ians 
of Quebec is the general occurrence of the richest graphite ore-bodies at the crests of 
folds or at other points where the structural relationships indicate that a relief of pressure 
has occurred, and this relationship is strikingly illustrated by the principal Port Elmsley 
deposit. 

It is possible that the main pit is situated close to the crest of the north limb of a 
major fold in the Grenville limestone and that the pitching anticline at the east end of the 
main pit is the continuation of this fold, but it seems more probable that the pitching 
anticline is a minor fold of the drag type developed on the north limb of a still larger 
anticline. The data from which this conclusion is inferred are the abundance of minor 
folds of the drag type in the limestone, as for example on the east face of the main pit 
directly above the southern termination of the graphite ore mass, the northeasterly strike 
of the limestone in the outcrops directly east of the main pit, and the unsymmetrical form 
of the main ore-body, the larger part of its mass forming the northwest limb of the saddle. 



32 

This explanation of the structure of the limestone adjacent to the graphite ore-body has 
obviously a bearing on development operations, for if the pitching anticline in which the 
saddle-shaped mass occurs is a major fold, the continuation of the graphite lead at the 
surface should be found to the south of the main pit; o'n the other hand, if the pitching 
anticline is a fold of the drag fype, the continuation of the graphite lead should be found 
to the east of the main pit. In either case, however, it is probable that the continuation 
of the lead beyond the southeast limb of the anticline, like the continuation of the north- 
west limb, is not of workable dimensions. 

With regard to the origin of the graphite Wilson says further: — 
The Port Elmsley graphite deposits, according to the sedimentary hypothesis, are 
presumably parts of highly carbonaceous beds in the Grenville limestone that have been 
broken up into detached masses by deformation. If a bed of this type were less competent 
than the associated limestone, it might be squeezed into a saddle-shaped mass similar 
in form to the main deposit. 

The association of the graphite with zones of silication in the limestone, and the 
increase in the graphite content of the ore in proportion to the intensity of silication, 
would seem to indicate, however, that the graphite was in some way associated with the 
intrusions of the pegmatitic rocks by which the silication of the limestone was effected. 
Gaseous or aqueous emanations derived from an igneous intrusion would tend to accumu- 
late at the crests of folds or other points where pressure was less intense, and in consequence 
silication might occur most completely at such points. There would likewise probably 
be a greater accumulation of graphite at such points, whether it emanated from the igneous 
intrusive or was derived from the carbon dioxide set free by the silication of the limestone. 
On the whole, therefore, the relationships of the Port Elmsley deposits can be best 
explained on the assumption that they are either igneous emanations or a product derived 
from the carbon dioxide of the limestone, rather than by the sedimentary hypothesis. 

The Port Elmsley ore consists of silicated Grenville limestone carrying 
disseminated flake graphite. The most highly silicated rock carries- the 
most graphite and forms the richest portion of the ore-body (15 to 20 per 
cent of graphite), and this grades into limestone carrying disseminated 
silicates and graphite. The latter is considered milling ore as long as the 
graphite content does not sink below about 5 per cent. The more common 
accessory minerals in the ore are diopside, orthoclase, calcite, pyrite and 
titanite. Analyses of several samples of the ore, made by H. A. Leverin, 
of the Mines Branch, showed a graphite content ranging from 6-67 per 
cent to 16-70 per cent. 

This property has been prospected by means of drilling probably to a 
greater extent than any other graphite deposit in the country, 28 holes 
having been put down between 1893 and 1917, in an endeavour to locate 
fresh ore. The results of this drilling, however, as well as of mining 
operations, do not tend to show that any graphite bodies of workable 
dimensions other than that exposed in the main pit, and described above, 
occur on the property. 

The workings consist of the original main pit, from which practically 
all the ore raised has been secured ; a shaft sunk some 400 feet to the north 
of the above, and a third small pit sunk about 100 feet to the south. The 
main opening consists of a shallow trench, or rather series of small trenches, 
for the greater portion of its 400-foot length, becoming wider and deeper 
towards its eastern end. At the eastern extremity, a shaft has been sunk 
to a depth of 250 feet, following the ore-body. This shaft is on an incline 
of about 60° N.W. for 150 feet of its depth, from which point it gradually 
approaches the vertical (see Fig. 3). Development of the ore-body 
underground has been carried out by means of three main levels run in both 
directions from the shaft for a distance of about 200 feet along the ore-body. 
The levels are placed at depths of 100, 150, and 200 feet, and work has^ 
lately been proceeding on a fourth, at 250 feet, which is being carried in an 
easterly direction, toward the crest of the anticline. 



33 




34 

In 1916, a shaft was sunk to a depth of 106 feet at a point 400 feet 
to the northwest of the main opening, and from it two drifts were run 
40 feet towards the latter at depths of 50 and 100 feet. No ore of any 
consequence is reported to have been met in these workings. 

Fig. 1 shows the general layout of the workings, position of drill holes, 
etc. 

The deposit, as exposed at the various levels, and more particularly 
in the deeper workings, consists of a series of three rich graphite bands, 
separated by graphitic limestone, rather than of a single ore-body. Of 
these bands, the centre one is the thickest and has been most worked, but 
the width of all three is decidedly variable in the different depths. The 
total thickness of the graphitic zone is 40 feet at its widest point, as so 
far determined, namely at the extreme eastern end of the main pit. While 
the graphite content of the rich zones will run as high as 20 per cent, the 
average is considerably lower; that of the graphitic limestone separating 
the bands of rich ore will possibly average from 3 to 5 per cent. 

The graphite is flake of good quality and fair average size. In addition 
to the ordinary, more or less equi-dimensional flake, small bodies of so-called 
"needle flake" are met with. (Plate XII.) The latter consists of lath-shaped 
individuals, whose length may be 5 or 6 times their width. Such material, 
however, breaks down readily, on milling, into particles of the ordinary 
flake form. No occurrence of vein graphite (plumbago) has been reported 
from this locality. , 

The main shaft is equipped with an inclined skipway to the second level 
and from here to the bottom of the shaft hoisting is performed with a 
bucket and winch. The ore is dumped into a bin at the shaft house, from 
which it is loaded onto waggons and teamed to the mill at Port Elmsley. 
Two boilers of 60 and 80 H.P. supply steam for the hoist, compressor, 
pumps, drills, etc. 

Mill 

In the original mill erected at Oliver's Ferry for the treatment of the 
ore from this property, the process of concentration was a wet one. The 
equipment 1 consisted of a battery of ten stamps, to which the ore was fed 
after being crushed to egg size, three buddies working in sequence, and a 
settling tank. The concentrate from the first buddle was fed to the 
second, and that from the second buddle to the third, thus effecting a 
progressive concentration of the graphite. The tails from all these buddies 
were returned to the stamps. The heads from the last buddle were trans- 
ferred to a circular settling tank (4 feet high, 4 feet in diameter at the top 
and 2 J feet at the bottom) and gently agitated with water, thus effecting 
a concentration of the gangue particles in the lower portion of the tank. 
This material was returned to the stamps. The graphite passed to a 
dryer, and thence to a reverberatory furnace, after which it was graded, 
by screening, into four products. The largest flake (60 mesh) was placed 
in a set of three small ball mills, set up in a special small chamber fitted 
with shelves around the walls. After grinding in these mills for some hours, 
the plates covering the feed-doors were removed and perforated plates or 
fine mesh screens were substituted. On re-starting the mills, the graphite 
was gradually discharged through the screens, the coarser flake settling 
on the floor of the chamber and the finer material on the shelves. 

^Rep. Ont. Bur. Min., 1896, p. 35. 



35 

Graphite for all sorts of purposes, including electrotyping, lubricating, 
pencils, stove polish and foundry facings, was turned out by this mill. 

In 1902, an old woollen mill at Port Elmsley on the River Tay, three 
miles east of the mine, was equipped with concentrating and refining 
machinery, and this mill is the one at present in use. The building is a 
3-story stone structure, and is situated on the bank of the river, which 
supplies water power for the operation of the machinery. The concentrat- 
ing process as originally installed here consisted of drying the ore, crushing, 
screening and concentrating by pneumatic jigs. The concentrates were 
then fed to burrstones, and a finished product made by a system of budd- 
ling, followed by screening. This installation was capable of treating 20 
tons of ore per day. 

In 1908, the above system was discarded and a system of wet concen- 
tration installed. The ore was crushed in jaw crushers and rolls, and 
then underwent a process of concentration in a classifier. The concentrates 
were dried in a revolving dryer, sized, and passed between burrstones to 
make a finished product. This installation, with various modifications, 
continued in use till 1911. 

In 1915, dry concentrating methods were again adopted, the system 
installed being the one that has found extensive adoption in Canadian 
graphite mills in recent years, and consisting in kiln-drying the ore, coarse 
crushing, alternate crushing between rolls of flour-mill type and screening, 
followed by concentrating on dry tables. The finishing process consisted 
in subjecting the concentrates to practically a duplication of the above 
treatment, employing rolls, screens, dry tables and burrstones. (For a 
detailed description of such a refining process, see pp. 74-8.) The above 
installation is capable of treating 100 tons of ore per 24 hours, consumes 
110 H.P., and requires 25 men for operation. The average graphite content 
of the ore treated by this process was stated to be 8 per cent, of which 62 
per cent was recovered. Of this, 82 per cent was No. 1 flake, and 18 per 
cent No. 2 flake and dust. 

At the time of writing (December 1918), experiments are being con- 
ducted with a novel system of film flotation, with a view to installing this 
method if the results are satisfactory. 

References: — 

Report of the Royal Commission on the Mineral Resources of Ontario, 
1890, p. 181; Annual Reports of the Ontario Bureau of Mines, 1893 to 
date. 

Geol. Surv. Can., Report of Progress, 1872-73, p. 178; Bulletin on 
Graphite, 1904, p. 22; Summary Report, 1917, Part E, p. 29. 

Catalogue of Economic Minerals of Canada, prepared for the Inter- 
national Exhibition, Philadelphia, 1876, p. 121. 

Mines Branch, Report on the Mining and Metallurgical Industries 
of Canada, 1907-8, p. 404. 

RENFREW COUNTY. 
Township of Brougham. 

Concession I, part of lot 20; Concession HI, lots 17, 18, and 19; 
Concession IV, part of lots 15, 16, 17, and 18. — Black Donald Mine, property 
of the Black Donald Graphite Company, Limited, Calabogie, Ontario. 
Mining operations have been confined entirely to the third concession, 
the principal openings being on the south edge of Whitefish lake. The 



36 

distance from the nearest shipping point, Calabogie, on the Kingston and 
Pembroke branch of the Canadian Pacific railway, is 14 miles, and trans- 
portation between mine and rail is effected by motor trucks. 

The deposit of graphite on this property was discovered in 1896, and 
work was commenced upon it in the same year by the Ontario Graphite 
Company, Limited, who erected a refinery at Ottawa to treat the ore 
chemically. Of the 300 tons of graphite ore produced in 1897, 200 tons 
were shipped in the crude state, and 100 tons were refined. In 1902, a 
three-story mill was erected at the mine, and a power plant was constructed 
on the Madawaska river, 2| miles to the southeast. In 1909, the mill 
was completely overhauled and an entirely new refining process installed 
by the Black Donald Graphite Company, Limited. The annual production 
of refined graphite of all grades from this mill since 1909 has greatly exceeded 
the combined production of all other Canadian refining plants. 

A great part of the underground workings on this property lies under 
Whitefish lake. A cave in, in 190|, on the shore line, due to carelessly 
mining too close to. the cap rock, resulted in a flooding of the shaft, necessi- 
tating its temporary abandonment. In 1904, the property was leased 
from the Ontario Graphite Company by P. McConnell, who constructed 
a dam around the break and shut out the water from that portion of the 
lake overlying the open cut workings. In 1908, the property was taken 
over on a long term lease by the present owners, the Black Donald 
Graphite Co., Ltd., who finally purchased the property from the Ontario 
Graphite Co., in 1917. 

The 400 H.P. generator at the Company's power house on the Mada- 
waska river furnishes all the power required in both mining and milling 
operations. The power is generated and transmitted to the transformer 
house at the mine at 4,400 volts, and is there stepped down to 550 volts. 
The Company has in use four 75 H.P. motors, one 60 H.P. motor, three 
30's, two 15's, and two 5's. In addition to the electrical installation, there 
are two 120 H.P. boilers, and the compressor house contains two Rand 
and one Blaisdell compressor, which have until recently been used for 
operating air-driven pumps and air drills. Two of the compressors and 
the air-driven pumps have lately been discarded, and an electrically 
driven centrifugal pump installed in the mine in their stead. 

A considerable amount of diamond drilling was done on the property 
in 1901-2, which resulted in the location of two distinct and well-defined 
veins. 

The Black Donald deposit exhibits very unusual features as compared 
with the general run of flake graphite occurrence, chief among them being 
its size and the richness of the ore. This deposit is the richest and largest 
body of flake graphite so far known in either the United States or Canada. 
The average graphitic content of the ore is 65 per cent, but zones of richer 
material, ranging as high as 80 per cent, occur locally. Much of the ore 
secured, therefore, has been pure enough in its natural state to find employ- 
ment in foundry work, and practically the entire output of the mine was 
sold in a crude state previous to 1909. The ore-body in the vertical vein 
worked consists of a more or less homogeneous mass of graphite, averaging 
about twenty feet in width. The maximum width, as determined in the 
underground workings, is 70 feet. The ore-body strikes northeast and has 
been traced for a distance of 800 feet, the width increasing from about 15 
feet at the westerly outcrop to 70 feet in the east workings. The deposit 
has a vertical dip, with well-defined walls, and pitches to the northeast 



DEPARTMENT OF MINES 

MINES BRANCH 

Hon. Martin Burrell, Minister R.G.M?Connell, Deputy Minister. 

Eugene Haanel, Ph.D., Director. 

1919 




Base map, Depl. of Interior 



515 



GRAPHITE OCCURRENCES 



IN 



BROUGHAM AND BLITHFIELD TPS., ONTARIO 

Scale; 3*95 miles to one Inch 

Reference 

1 Black Donald Graphite Co. 
(•) Mine equipped with mill 
O Undeveloped prospect 



37 

at an angle varying from twenty to forty degrees. It is capped by lime- 
stone, and has been found to extend to a depth of at least 125 feet. At 
this point it appears to be cut ojf by limestone. This may be due to 
faulting, or more possibly, folding. Its thickness varies from eighteen 
to twenty-four feet for a proved distance of 600 feet, from which point 
it swells out to a width of 70 feet. It is enclosed in crystalline, Grenville 
limestone, which is graphitic for several feet on each side of the ore-mass. 
At several places in the underground workings, narrow dikes of pegmatite 
have been encountered cutting across the vein, and these are thus younger 
than the latter. While the ore consists of flake graphite, the greater part 
of the flake is of such small size as to preclude being classed as No. 1. It is, 
in fact, so fine as to have caused the misleading term "amorphous" to be 
commonly applied to the intermediate and lower grades of Black Donald 
graphite. Such a term is incorrect, however, as the fine-grained graphite 
is essentially of flake form. Disseminated through this fine graphite is a 
certain amount of larger flake. The proportion of such flake to fine, dust 
graphite in the average ore, is approximately 1:3: that is, taking the 
average grade of ore as containing 60 per cent of graphite, about 15 per 
cent will consist of flake and 45 per cent of dust. 

The principal impurity in the ore is calcite, which occurs both inti- 
mately mixed with the graphite and in the form of narrow seams or 
stringers. Chlorite, as well as small amounts of other silicates, also occurs. 

While the deposit presents much similarity to a true vein, the 
fact that the graphite is of the flake variety tends to discount this view. 
So far as known, vein graphites are invariably of the crystalline or plum- 
bago variety, and veins of such material have not heretofore been found 
to carry even a small proportion of flake. Then again, such veins are 
almost invariably narrow, and, in the case of the Canadian occurrences, 
usually of decidedly irregular form. It seems likely, therefore, that the 
Black Donald ore-body is of metasomatic origin rather than a true vein ; 
that is, that the graphite constitutes a replacement product of a certain 
zone of the limestone enclosing the deposit, and that, while exhibiting 
certain unusual features, the latter has an analogous origin to other flake 
deposits of the Pre-Cambrian rocks in Ontario and Quebec. In this 
particular instance, a far more intense degree of graphitization of the lime- 
stone than usual would appear to have taken place, accompanied by a 
correspondingly lesser degree of silication. In view of the fact that the 
ore-body tends to increase in width from west to east, and that it appears 
to pinch out in the former direction, it would seem probable that the deposit 
may be in the nature of a saddle-shaped mass of graphite developed on an 
anticlinal fold in the limestone. (See Fig. 2, p. 31.) 

As already stated, most of the mining work has been carried on near 
the shore of the lake, the shafts, drifts, and stopes being carried along the 
easterly extension of the deposit. The first shaft sunk reached a depth 
of 80 feet and was vertical. From the bottom of the shaft a level was 
run northeast, under the lake for 200 feet, and southwest 24 feet. The 
east drift was stoped out to a height of 50 feet for a distance of 120 feet, 
and 30 feet for the remainder, at which point the ore-body had a width of 
26 feet. A number of smaller pits and trenches were opened up still farther 
to the southwest along the ore-body. Three diamond drill holes, put down 
in 1901 on the 80-foot level in the main shaft, proved ore to a further depth 
of 40 feet. In 1901 water from the lake broke through into these workings 
and necessitated their abandonment. In the following year, a 34-foot 



38 

vertical shaft was sunk in an old pit 200 feet west of the main shaft, from 
the bottom of which a drift was carried 50 feet to the west, from which 
point an inclined raise was driven a distance of 30 feet to the surface. In 
this drift, the ore-body was found to widen over a short distance to 46 
feet. The extent of the workings to date show a proved length of ore- 
body of 800 feet, with the easterly workings still in ore, and a gradual 
widening of the deposit from 15 feet to the extreme western end to 70 feet 
at the east face. 

In 1905, following an unsuccessful attempt to reopen the flooded 
workings, a new shaft was sunk at a point 100 feet west of the original main 
shaft. This was put down on an incline of 30 degrees northeast and reached 
a depth of 170 feet on the incline. From this shaft the ore-body was 
stoped out in both directions, but principally to the east, and the opening 
was later converted into an open pit. This pit continued to supply most 
of the ore mined until 1916, a depth of 145 feet, vertical, being reached. 
Hoisting from the present workings is done by an inclined skipway. 

Prior to 1917, sufficient ore was mined during the summer months to 
keep the mill supplied for the whole year; but for the past two years the 
mine has been operated on a double shift, summer and winter. 

Thirty feet southeast of the main ore-body, and at ninety feet depth, 
a fourteen-foot, flat-dipping body of graphite was struck. Mining oper- 
ations on this vein produced some of the richest flake ore ever raised on 
the property. After satisfactorily proving this second vein, operations 
were resumed in the big pit. 

At the present time work is proceeding at a point 500 feet northeast 
of the shaft head and 200 feet below the level of the lake, where a stope is 
being carried to the northeast. The ore-body here has a width of 70 feet. 

In addition to the three story refinery, boiler, compressor and hoist 
houses, warehouse, and other mine buildings, a small village of some 
forty dwellings (Black Donald P.O.) has grown up on the property for 
the accommodation of the employees. 

Mill. 

While various modifications of the system installed by the original 
owners were made from time to time, operations did not prove satisfactory 
until an entirely new refining process was installed by the present owners 
and operators of the, property in 1909. The buddle system practised here 
is the same method of concentration, with modifications to meet the local 
conditions, as was installed in the earliest Canadian mills, and it is worthy 
of note that their use has been persisted in despite the wide-spread adoption 
of numerous other and varied concentration processes that have been 
evolved in more recent years. The mill has a capacity of twelve tons of 
refined graphite per day of two shifts. The Nos. 1 and 2 flakes 
produced are reported to average about 88 per cent carbon and owing to 
the absence of siliceous material in the ore, are particularly well adapted 
to the lubricating trade. 

A flow sheet of the mill 1 is given on page 82. 

References : — 

Annual Reports of the Ontario Bureau of Mines, 1896 to date, more 
particularly 1896, 1901, and 1903. 

Geol. Surv. Can., Bulletin on Graphite, 1904. 

Mines Branch, Report of the Mining and Metallurgical Industries of 
Canada, 1907-8, p. 406. 

^ote. — The mill has sinoe been remodelled for Callow pneumatic oil flotation. 




VERTICAL SECTION 
MAIN MINE WORKINGS 

BLACK DONALD GRAPHITE COS MINE 

Lots 17 & 18. Concession III 
Brougham Tp., Ont. 

Horizontal Scale 



Vertical Scale 



cut timbered oyer 
Underground Workings 



67945— p. 38 



Fig. 4a. Section through working, Black Donald Mine, Brougham Township, Ont. 




Fig. 4. Plan of workings, Black Donnlil Gr.tphiir < 'ompany, township ol Brougham, Ont. 



39 



Township of Lyndoch. 



Concession II, lots 1 and 2. Owned by Messrs. Beidelman and Lyall, 
701 Transportation Building, Montreal. Only a small amount of work of a 
prospecting nature has been carried out on this property, which was not 
visited by the writer. The following details regarding it have been kindly 
supplied by the owners. 

The property lies 25 miles from the nearest rail point, Caldwell station, 
on the Ottawa-Parry Sound branch of the Grand Trunk railway, and 33 
miles southwest of Renfrew. The workings lie on the left bank of the 
Madawaska river, a few hundred feet from the water. The trend of the 
deposit is northeast, and the main graphitic zone, as proved by trenching, 
is about 250 feet wide, though outcrops of graphite are also found outside 
of this .belt. Trenching has been carried out over a total distance of 1,800 
feet along the strike of the deposit and has exposed graphite for the entire 
distance. The deepest pit on the property is a 7'X9' shaft, sunk to a 
depth of 35 feet: this was in good ore all the way. The ore consists of 
flake graphite, and rather resembles that of the Black Donald mine, in 
Brougham township, being made up largely of very small flake carrying a 
proportion of larger flake scattered through it. The graphitic zone would 
appear to comprise several bands of richer ore separated by belts of more 
or less graphitic limestone. The country rock is crystalline, Grenville 
limestone. 

The present owners acquired the property in 1917, and carried out 
most of the development work that has been done, with the exception of 
the main shaft, which was put down in 1917 by Mr. McHale, of Ottawa. 

A sample of ore from this property was made the subject of concentrat- 
ing tests by the Callow oil flotation system, the work being done at the 
Ottawa office of the General Engineering Company. These tests showed 
that by this system of treatment, there could be produced from every 
ton of ore : — 

143 pounds No. 1 flake (-f-80 mesh) assaying 89 per cent carbon, and 
154 pounds No. 2 flake ( — 80 mesh) assaying 85-1 per cent carbon, with 
a recovery of 91 • 1 per cent of the graphite in the ore. Assay of the sample 
treated showed a carbon content of 12-9 per cent. 

Fig. 5 is a surface plan of the workings and outcrops on this property. 

Additional Graphite Localities in Ontario. 

In the Report of the Ontario Bureau of Mines for 1904, p. 93, a graphite 
deposit is stated to have been worked in 1913 a few miles from Kinmount 
station in Victoria county. There is no record of any further development 
of this property. 

On lot 34, concession VIII, township of Denbigh, in Addington county, 
a small amount of mining was carried out during 1902-3, by J. G. Allan, 
of Hamilton, Ont. In the bulletin on Graphite, issued by the Geological 
Survey in 1904, p. 25, the ore on this property is stated to run as high as 
76 per cent carbon, with an average of 50 per cent, and to be of the amor- 
phous variety. The latter term probably signifies flake so small as to 
give the ore a powdery character. . About 200 tons of ore were mined 
from a shaft 50 deep feet and shipped in the crude state. No further work 
has been performed at this locality. On lot 1, concession VIII, of Ashby 
township, (the adjoining lot to the west) similar ore is stated to occur. 

945—4 



40 




41 

In Annual Report of the Geological Survey, vol. VII. 1894, p. 11R, fine- 
grained ("amorphous") graphite is stated to occur on lot 13, concession 
VIII, township of Marmora, in Hastings county. An analysis of a sample, 
made in the laboratory of the Geological Survey, showed a graphite content 
of 72 per cent. 

. On lots 13 and 14, concession IV, township of Blithfield, in Renfrew 
county, a deposit of flake graphite is stated to have been worked to a small 
extent previous to 1896. (Bulletin on Graphite, p. 25). 

Other localities where graphite is reported to occur, but about which 
no further published information is available, are: — ■ 

Frontenac county: township of Bedford, IX, 18. 

" " Loughborough, IX, 6. 

Lanark county " North Burgess, I, 10. 

North Elmsley, IX, 7. 
" " Darling, near Tatlock. 

Hastings county " Dungannon, XIII, 28. 

Renfrew county " South Canonto, III, 23. 

Westmeath, Front A, 21. 

Lake of the Woods. 

(Carbonaceous Schists.) 

Enquiries having been received by the Mines Branch as to the nature 
of the carbonaceous schists of this region, the following extracts from 
reports on this section are quoted to show the character of the carbon 
contained in these rocks: — 

Associated 1 with the soft, fissile, hydromicaceous or magnesian schists of the lake, there occur in several local- 
ities bands of jet black carbonaceous or sub-graphitic schists. These schists have a very characteristic vesicular 
structure and are strongly impregnated in most cases with pyrite. The present note is not for the purpose of calling 
attention to any economic value of these schists, but rather the reverse, viz., to point out their worthless character 
from an economic standpoint and so endeavour to save time and money to prospectors, who may be tempted to 
explore those bands in the belief that they have discovered a graphite mine. As I have been consulted several 
times by prospectors at Rat Portage respecting the value of these carbonaceous schists, and as some seemed per- 
suaded of their graphitic character, it may be useful to repeat that spacimens from the band of carbonaceous schists 
that crops out on the shore, one mile south of the mouth of Ptarmigan Bay, examined in the laboratory of the Survey 
by Mr. Frank Adams, yielded only 5-773 per cent of carbonaceous matter, after drying at 100°C; and another speci- 
men lost 7-47 per cent on ignition, nearly all, probably, carbonaceous. The opinion of Mr. W. F. Downs, chemist 
to the Joseph Dixon Crucible Co., Jersey City, is decisive as regards its commercial value. Half a dozen specimens 
from different localities were submitted to him, and speaking of the general character of the schist, he says: — 
" It is hardly plumbaginous, though certainly highly carbonaceous, and it lacks most of the distinguishing features 
of graphite. Its only possible economic value would be in the manufacture of cheap facings, but the ingredients of 
these are very cheap, so I see no value in it." 

The origin 2 and structure of these schists presents a difficult problem, A chemical analysis yields very little 
evidence as to the origin. So much alteration has taken place both in the removal of certain ingredients, and the 
ntroduction of others that the evidence obtained from an analysis is largely of a speculative nature. 

An analysis gives: — 

SiO a 76-10 

Ti0 2 0-44 

Fe 2 3 7-48 

A1 2 3 4-14 

CaO : 0-74 

MgO 0-84 

Sulphur 0-74 • 

Carbon 8-24 

Loss on heating to 150°C 10 

The writer would draw attention to the form in which the carbon now occurs. Very little, if any, is true graphite 
but is amorphous carbon and can be burnt in air at temperatures no higher than a Bunsen flame. It is quite reason- 
able to expect that if this were organic matter deposited simultaneously with tho^e Keewatin rocks, it would by 
this time have been converted into true graphite. All our Archaean rocks containing carbon at all, have it in tha 
form of graphite. 

'Lawson, A. C, Geol. Surv. Can., Ann. Rep., 1885, Part CC, p. 150. 
Greenland, G. W., Trans. Can. Inst., Vol. XVI, 1013, pp. 586-9. 

67945— 4 £ 



42 

Carbonaceous schists, usually pyritiferous, and in a general way similar 
to those described above, occur also in the Kenora district, 14 miles south- 
west of English River station, on the Canadian Pacific railway; also 
in the Nipissing district, McCart township, concession V, lot 7, northwest 
of Porquis Junction, on the Timiskaming and Northern Ontario railway. 
Finer-grained carbonaceous schist, running about 8 per cent carbon, occurs 
on the north shore of Beaver lake, in Saskatchewan, near the Flin Flon 
and Mandy mines. 

PROVINCE OF QUEBEC. 

Graphite mining in Canada had its inception in the Province of Quebec, 
about the year 1846, when a deposit of crystalline graphite, or plumbago, 
was worked on lot 10 in range V of the township of Grenville, in Argenteuil 
county. Work was continued for a few years, and the property then lay 
idle for a number of years, being subsequently re-worked as the Miller mine, 
and later again, in 1899, as the Keystone mine, 

Disseminated flake graphite was first mined in 1866 on lot 24 in range 
VIII, and lots 23 and 24 in range XI, of the township of Lochaber, in Labelle 
county. The output of these mines was refined at a mill erected on 
the Blanche river, on lot 28 in range X of the above township. These 
operations were conducted by the Lochaber Plumbago Company. At 
this period, considerable interest commenced to be evinced in the possi- 
bilities of the graphite resources of this district, and Logan, in the Report of 
Progress of the Geological Survey for 1863-6, pp. 22-27, describes a number 
of localities in Buckingham and Lochaber townships at which graphite 
deposits had been discovered and in some cases worked in a small way. 
Among these early operators, the New England Plumbago Company is 
stated to have acquired mining rights on lot 22 in range VII of Buckingham, 
as well as on lots 1 WJ and 2 EJ in range III, and lot 17 in range IX of the 
township of Wentworth. On pp. 218-23 of the above report, T. Sterry 
Hunt discusses at some length, the quality, occurrence and possible origin 
of the graphite from the Buckingham district. 

In the Report of Progress for 1871-2, p. 148, graphite is stated to have 
been worked during the preceding three years on lot 28 in range VI of 
Buckingham by the Canada Plumbago Company, the production being 
450 tons. 

H..G. Vennor, in Report of Progress for 1873-4, pp. 139-43, describes 
a number of graphite occurrences in the township of Buckingham, some of 
which had been worked in a small way. 

In the Report of Progress for 1876-7, pp. 308-20, Vennor enters into 
greater detail regarding the occurrences of graphite in this area and the 
mining work carried out upon them. The most important operations to 
date appear to have been those of the Buckingham Company, on lot 27 
in range VII, and of Messrs. Pugh and Weart, on lot 27 in range VI. The 
properties of the Canada Plumbago Company were taken over in this year 
by tKe Montreal Plumbago Company. Graphite mining appears to have 
about come to a standstill in 1876. On pp. 489-510 of the above Report, 
G .C . Hoffmann gives the results of a number of analyses conducted on samples 
of Canadian graphite, both crude and refined, and discusses the relative 
quality of Canadian and foreign graphites. 

In Report of Progress for 1882-4, p. 30 — 2 J, J. F. Torrance states that 
in these years alj Canadian graphite mines were idle, and attributes the 
reason for the stagnation of the industry to the poor grade of refined product 
turned out by the mills. 



43 

In 1888, mining was resumed at several localities in Quebec, and was 
continued thenceforth intermittently till 1899, the chief operators being 
the Walker Plumbago Mining Company, range VIII, lot 19; the North 
American Graphite Company, range VI, lot 28; and the Buckingham Gra- 
phite Company, range VI, lots 26 and 27, all in the township of Buckingham. 

In the Annual Report for 1897, Vol. X, pp. 66-73 S, A. A. Cole des- 
cribes the deposits and workings at the above mines in detail. 

All the mines in the Buckingham district were practically idle from 
1899 till 1906. In the latter year, several new mills were erected, two near 
Buckingham and one at Calumet, in Argenteuil county; and from that time 
to the present, operations have been conducted intermittently at the various 
properties. Several other mills have been put up and other deposits devel- 
oped, but none of the mines or mills have been run continuously, and 
there have seldom been more than a couple of mills in operation at one 
and the same time. With the abandoning of the original wet system of 
concentrating, which, while perhaps wasteful of graphite, was cheap to 
operate, graphite refining became largely the subject of experiment on a 
large scale. These experiments have, on the whole, been both unsatisfac- 
tory and costly, with the result that the graphite industiy is still on a far 
from established basis. It is to be hoped that the work that has lately been 
done in adapting oil flotation to graphite ores, may remedy this state of 
affairs and enable the exploitation of graphite deposits to be taken up with 
a greater measure of success and profit than has heretofore been the case. 

Hitherto, a graphite content of at least 12-15 per cent has been con- 
sidered lequisite in an ore that would repay treatment by the concentration 
methods in use, and, consequently, large bodies of lower grade ore have 
been left at many of the mines as unprofitable to work, while seaich was 
made for fresh deposits of rich material. Much of this low grade ore should 
prove capable of profitable treatment by flotation. Probably the maximum 
graphite content of the flake graphite ores of the district is 25-30 per cent, 
but only selected material will run as high as this. This rich ore occurs 
as streaks, which merge into material of gradually diminishing graphite 
content, and when the latter falls below 10 per cent, a deposit is usually 
abandoned. Flotation, which combines cheaper and more efficient methods 
of recovery of the graphite content of the ore with the ability to treat 
considerably lower grade material, should do much to place the graphite 
industry on a profitable footing, if this is in any way feasible. 

The graphite deposits of Quebec Province lie mainly in the township 
of Buckingham, where they have been found to extend almost from the 
border of the Palaeozoic rocks, that overlie the Archaean in the southern part 
of the township, as far north as range XII. This district is served by the 
North Shore, Montreal-Ottawa branch of the Canadian Pacific railway, the 
nearest station being Buckingham junction, which connects with the town 
of Buckingham, 3 miles to the north, by a spur line. 

Scattered deposits also occur in the county of Argenteuil, to the east 
of the above area, while occurrences have been recorded, but not worked, 
at many points throughout the area of crystalline rocks extending westward 
into Pontiac county. The deposits hitherto found in this latter district 
appear to be too small to be of economic importance. 



44 

The fluctuating production of graphite from this Province from 1898 
to 1918 is shown by the figures of value in the appended table: — 

Value of Graphite Produced in the Province of Quebec, 1898-1918. x 



Year. 


Value. 


Year. 


Value. 


1898 


$ 
8,500 
14,257 
9,464 
4,690 
2,160 


1909 . < . 


$ 
10,339 
15,898 


1899 , 


1910. . . 


1900 


1911 

1912 


33 613 


1901 


50,680 
9,620 

18,886 
2,416 

75,776 

99,024 


1902 


1913 

1914 


1903 


1904 


2,300 


1915 


1905 


1918 . 


1906 


8,300 

5,000 

165 


1917 

1918 


1907 


17,760 


1908 









The more important occurrences of graphite in the Province are listed 
in the following pages. In addition to these, outcrops of graphite, both 
of the flake and plumbago varieties, occur at many scattered points in the 
townships of Buckingham, Lochaber, Chatham, Grenville and others, 
in Pontiac, Hull, Labelle and Argenteuil counties. 



ARGENTETJIL COUNTY. 
Township of Grenville. 

Ranges II and III, lots 16. — These lots were worked in a small way in 
1901 by the Calumet Mining and Milling Graphite Company, who mined 
about 100 tons of ore. In 1906, the Company erected a mill near Calumet 
station and carried out some mining during this and the succeeding two 
years. Both mine and mill have been idle since 1908. 

The workings comprise several small surface pits, an open cut with a 
50-foot shaft sunk at one end, and a drift carried into the side of a ridge 
close to the mill. This drift has now caved in, and it was found impossible 
to make any examination of it. It is stated, however, that neither in this 
nor in any of the other workings were graphite bodies of any size encoun- 
tered. The graphite occurrences on these lots consist mainly of plumbago, 
which is found in veins ranging from 3 to 18 inches in width. About 100 
tons of such material is stated to have been obtained during the period of 
operation. 

The property lies just west of Calumet station, on the Montreal- 
Ottawa, North Shore line of the Canadian Pacific railway. The mill 
which is situated alongside the track, is a large, 3-story, wooden structure, 
and was equipped with dry concentrating machinery, run by electric power. 
Very little ore is reported to have been treated. Much of the electric 
equipment has now been removed and part of the building has subsided. 2 

The property is at present owned by the estate of J. K. Ward; admin- 
istrator, C. I. Root, 8 Rosemount Avenue, Westmount, Que. 
References : — 

Reports of the Department of Mines, Province of Quebec, 1901-1908. 

Monograph on Graphite, Mines Branch, 1907, p. 40. 

1 Compiled from Annual Reports of the Department of Mines of the Province of Quebec. 

2 Note. — The mill has since been converted into a calcining plant for magnesite. 



DEPARTMENT OE MINES 

MINES BRANCH 

Hon. Martin Burrell, Minister, R.G. M? Connell, Deputy Minister 

Eugene Haanel. Ph.D., Director. 

1919 




Reference 

1 Calumet Mining and Milling Graphite Co. 

2 Miller or Keystone 

3 National Graphite Co. 

4 Canadian Graphite Co. 

5 Patterson 
(•) Mine equipped with mill 
% Mine 
O Undeveloped prospect 



Base map, Dept. o] Interior 



GRAPHITE OCCURRENCES 

IN 

GRENV1LLE AND WENTWORTH Tps., QUEBEC 

Scale; 3-85 miles to one Inch 



45 

Range V, lot 10. — Known as the Miller mine. This occurrence of graphite 
was perhaps the earliest to be exploited in Canada, having been worked 
around the year 1845 by R. V. Harwood, of Vaudreuil. The deposit was 
examined, and reported on, by Logan in several of the earlier (1845 to 1863) 
reports of the Geological Survey. Five veins of plumbago were stated to 
occur, varying from 5 to 22 inches in thickness. After lying idle for a 
number of years, the property was taken over in 1889 by Messrs. Rae & 
Co., of Montreal, but very little work was done. In 1900, the Keystone 
Graphite Company, of Wilkesbarre, Pa., conducted operations, and are said 
to have shipped 25 cars of hand picked plumbago. This constitutes the 
last work on the property. 

While a few small surface pits have been opened at various places on 
this lot, operations have chiefly centered in one main excavation. This is 
an open cut, 200 feet long, 30 feet deep for the most part but increasing to 
75 feet in a shaft-like opening midway of its length, and 20 feet wide at 
both ends, while at the shaft the width increases to 50 feet. The course of 
this opening is mainly northeast, but is not constant for its entiie length, 
the pit rather describing the arc of a circle. 

The greater part of the graphite found here is of plumbago type, with 
a small amount of large flake included in the associated minerals. The 
ore-body is of contact metamorphi,c type, similar to that occurring on lots 
15 and 16, range VII, township of Amherst, about 30 miles to the north. 
The plumbago occurs associated with such minerals as wollastonite, 
vesuvianite, garnet, titanite, pyroxene, calcite, etc., the whole forming an 
aggregate of coarsely crystallized individuals and probably constituting a 
silicated zone at the contact of an i,ntrusive with crystalline limestone. 
The graphite is thus intimately intergrown, for the most part, with foreign 
mineral substance, and though a proportion can be cobbed sufficiently clean 
to be marketed, a greater proportion will require milling in order to turn 
it into a No. 1 product. 

All of the graphite shipped from this mine was in a hand cobbed state, 
there being no mill on the property. In addition to the type of ore des- 
cribed above, small veinlets of plumbago are seen traversing the country 
rock on the west side of the pit. Most of the richer ore is reported to have 
come from the shaft put down in the middle of the cut. This shaft has 
been sunk alongside a well defined slip-face or fault, (see Plate XVI) having 
a northeasterly trend. 

The intrusive, to the action of which the formation of the ore-body 
may be ascribed, is not exposed in the accessible portions of the workings 
and material of a pegmatitic nature was not observed on the dumps. The 
latter contain, however, considerable quantities of a grey, porphyry-like 
rock, which is of younger age than the other members of the Archaean 
complex and cuts the latter at the north end of the big pit. 

Some development work was commenced in 1899 by the National 
Graphite Company, of Scranton, Pa., on the adjoining lot to the east 
(V. 9), but was soon afterwards abandoned. 

The property lies 3J miles by road north of Grenville station, on the 
Montreal-Ottawa, North Shore line of the Canadian Pacific railway, and 
is understood to be owned by S. Hirsch, Wilkesbarre, Pennsylvania. 
References ' — 

Geol. Surv., Can., Report of Progress, 1849-50, p. Ill; 1851-2, pp. 42 
and 118; Ann. Rep., Vol. IV, 1888-9, p. 139K; Vol. XII, 1899, p. 73 0; 



46 

Summary Report, 1916, p. 214; Catalogue of Economic Minerals of 
Canada at Philadelphia International Exhibition, 1876, p. 121. 

Report of Department of Colonization and Mines, Province of Quebec, 
1900, p. 16. 

Monograph on Graphite, Mines Branch, 1907, p. 39. 

Township of Went worth. 

Range III, lots 1A and IB. — This property was taken up for graphite 
originally by the New England Plumbago Company, in 1863. No work, 
other than of a prospecting nature was done, however, until 1911, when the 
Canadian Graphite Company, 34 Coristine Building, Montreal, Que., 
acquired the property. This Company, who are the present owners, have 
carried out a certain amount of development work on various parts of the 
above lots, and by surface pits and trenches have shown the presence of 
graphite over a considerable area. In 1918, lot IB was diamond-drilled 
by an American syndicate, under option of purchase, and the results are 
stated to have shown the existence of a large body of disseminated flake 
ore. 

The graphite occurs disseminated in a band of calcareous gneiss some 
30 feet wide, which extends for a distance of 600 feet along and paralleling 
the side of a low ridge. This band is in contact to the south with a body of 
anorthosite, and to the north with a belt of quartzite. The greatest depth 
reached in the drilling operations on this ore-body was 212 feet, and at this 
depth the hole is stated to have been still in ore. The average graphite 
content is given as 15-20 per cent, and the flake is of good size and quality. 

A 100-foot adit was driven into the south side of a parallel ridge, 
about i mile to the south of the above deposit, with the intention of working 
several veins of plumbago which outcrop here. Results were not encour- 
aging, however, and work was abandoned. 

The property lies 12 miles north of Lachute, on the Montreal-Ottawa 
North Shore line of the Canadian Pacific railway. 

The adjoining lots to the east, namely lots 1A and IB, in the township 
of Gore, also carry showings of graphite, and a small amount of surface 
work has been conducted on them. This property is owned by T. W. 
Patterson, 34 Coristine Building, Montreal.*; 



LABELLE COUNTY. 
Township of Amherst. 

Range VII, lots 15 and 16. — This property was first actively exploited 
in 1909 by Graphite, Ltd., of Montreal, who put down a 90rfoot shaft, 
besides carrying out a lot of surface work. Work was prosecuted for several 
years, and in 1912 a large mill was erected. After only a few months 
work, however, the Company went into liquidation in 1913. For six 
months during 1914, work was conducted under lease by Messrs. Reilly & 
Layfield, and again for a few weeks in 1916, under option, by the Multipar 
Syndicate, of London. Since the last-named ceased work, the property 
has been idle: it is now understood to be under purchase by Graphite 
Products, Ltd., of 55 St. Francois Xavier Street, Montreal, who contemplate 
installing flotation treatment in the mill, and who also own lots 11 to 14 
and 20, 21 in the same range. 



CANADA 

DEPARTMENT OF MINES 

MINES BRANCH 

■Hon.mH.rtin Burrell, Minister, R.G.M9Connell. Deputy Minister 

Eugene Haanel, d h D., Director. 

1919 




46 oo 



Base map, Dept. of Interior 

GRAPHITE OCCURRENCES 

IN 

AMHERST Tp., QUEBEC 

Scalp; 3-95 miles (o one Inch 



Reference 

1 Graphite Products Ltd. 
® Mine equipped with mill 
O Undeveloped prospect 



LOT IB 




4C0 200 



LOT I 



T p 



* * IS % % * 



* Pifs Showing w 
i- graphite in gneiss 




Section through 
Graphite deposit 
along X—Y 



Fig. 6. Plan and section of graphite deposit, lots 1a and 1b, township of Wentworth, 
and lots 1a and 1b, township of Gore, Que. 

The graphite body on these lots is in the nature of a contact deposit 
between crystalline limestone and an intrusive rock, probably of gabbro 
type. The occurrence closely resembles that at the Miller mine, on lot 10 



48 

in range V of Grenville township, being characterized by an abundance 
of typical contact metamorphic minerals, such as wollastonite, diopside, 
titanite, hornblende, vesuvianite, scapolite, etc. These minerals, together 
with the graphite, occur as an aggregate of coarsely crystallized individuals 
in a silicated zone in the Grenville limestone, probably at its contact with 
pegmatite. The underground workings, being flooded when the property 
was visited, could not be examined. 

These workings consist of a shaft 125 feet deep, from which levels were 
run at 40, 80, and 125 feet. The extent of these levels was not ascertained 
but is said to be considerable. From the uppermost level, a raise has been 
put through to the surface, terminating in an open cut, 50 X 30 feet and 
30 feet deep. 

While a certain amount of flake graphite occurs disseminated in the 
adjacent limestone and also, in greater quantity, in narrow bands in this 
rock, the majority of the ore consists of foliated graphite, approaching 
plumbago in character. Most of this, however, is so intimately associated 
with foreign mineral substance as to require milling in order to fit it for 
market. A certain proportion might, perhaps, be cleaned sufficiently 
by hand cobbing to render it suitable for crucible work, but it would 
probably prove more expedient to put the whole of the ore through a milling 
process. 

The irregular form of the ore-bodies, which appear to consist of 
pockety and discontinuous masses, enclosed in limestone, necessitate the 
mining of large quantities of dead rock, so that the proportion of graphite 
to the amount of rock mined is low. 

The workings are connected by 150 feet of tramway with the drying 
kiln, situated back of the mill building. The latter is a large 3-story, 
wooden structure equipped with dry concentrating machinery of the usual 
type (see pp. 74-8), and has a capacity of 200 tons of ore per 24 hours. 

According to Cirkel 1 , the graphite bearing zone here has a wid th of 
200 feet and extends for a distance of over two miles. In this zone occur 
lenticular bodies and nests of graphite ranging up to several feet in diameter, 
with other irregular shoots of both plumbago and disseminated flake. 
From 640 tons of rock mined, 15 tons of cobbing ore and 227 tons of milling 
ore were obtained. By cobbing ore is meant ore that can be cleaned 
sufficiently by hand to be marketed without undergoing crushing and 
refining. The milling ore is stated to carry about 15 per cent of graphite. 

The mine lies 12 miles from St. Jovite station, on the Montreal-Mont 
Laurier branch of the Canadian Pacific railway. 
References : — 

Reports of the Department of Mines, Province of Quebec, 1910 to date. 

Monograph on Graphite, Mines Branch, 1907, p. 42. 

Geol. Surv. Can., Memoir 113, 1919, pp. 38-43. 

Township of Buckingham. . 

Range IV, lots 1, 2, 3, ~ 4, and j 5. — Property of the Quebec 
Graphite Company, Craven House, Kingsway, London, W.C. Mining- 
was commenced here in 1912 by the Quebec Graphite Company, who 
erected a mill and continued to operate till 1914. In 1915, the Company 
was reorganized and its name changed to the New Quebec Graphite 
Company. The latter have produced steadily from 1915 to 1918, but 

1 Trans. Can. Min. Inst., Vol. xv, 1912, pp. 261-9. Can. Mining Journ., Vol. 33, 1912, pp. 435-7. 



CANADA 

DEPARTMENT OF MINES 

MINES BRANCH 

Hon.Ma.rtin Burrell, Minister, R.G.M?Connell. Deputy I 
Eugene Haanel. Ph.D., Director. 
1919 




Reference 

1 New Quebec Graphite Co. 

2 Bell Graphite Co. 

3 Plumbago Syndicate [Dominion mine) 

4 Pugh and Weart 

5 Buckingham Graphite Co.(North American mine) 

6 M. P. Davis {Walker mine) 

7 Consolidated Graphite Mining and 
Milling Co. {Peerless mine) 

8 Lochaber Plumbago Mining Co. 
® Mine equipped vrith mill 
• Mine 
O Undeveloped prospect 



Base map. Dept. of Interior 



GRAPHITE OCCURRENCES 



BUCKINGHAM AND LOCHABER TPS., QUEBEC 



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49 

operations were suspended in the latter year, pending alterations to the 
mill. 

Most of the ore raised has been obtained from a number of surface 
openings scattered over the above lots, the majority being on lot 3, on 
which lot the mill also is situated. Two shafts were also sunk on this lot, 
but encountered little ore and were abandoned after reaching a depth 
of 70 feet. 

All the graphite encountered on this property is of the disseminated 
flake type, which occurs in a series of bands in calcareous gneiss. No very 
large deposit has hitherto been discovered, but small bodies of ore appear 
to be distributed rather extensively all over the property. From exposures 
in one of the larger surface pits, it would appear probable that at this 
locality, as at a number of others carrying flake graphite, both in Quebec 
and Ontario, the graphite ore-bodies are to be looked for at or near the 
crests of anticlinal or drag folds in the gneiss (see Plate XVIII) . In several 
of the pits, slickensided walls were noticed bordering the graphite bodies. 

The graphitic zones are commonly highly weathered at the surface, 
due to the decomposition of sulphides present, and a deposit of rusty- 
coloured, sandy material is often a good indication of graphite. The 
weathering, however, is purely surface and persists only for a few feet 
down. 

A large portion of the above lots is bush-covered, and carries a soil 
overburden, so that trenching is generally necessary in prospecting for 
new ore-bodies. 

The ore consists of disseminated flake of good quality and size, mixed 
with mica, quartz, calcite, pyrrhotite and lime silicates. The average 
mill-feed is stated to run 14 per cent graphite. Here, however, as at other 
mines in the district, only the richer ore is considered a milling proposition, 
and the outer zones of lower grade rock which usually border the richer 
portions of the deposit are left. The graphitic bands are usually narrow, 
a thickness of 9 feet being the extreme. 

Mill. 

The mill is a 3-story wooden structure, with a capacity of 40 tons 
of ore per 24 hours. The concentrating system is a wet one, designed 
by Krupp, and is modelled along lines quite distinct from any other graphite 
mill in the country. The greater part of the mill equipment was supplied 
by the Krupp firm, and the concentrating process consists, briefly, in 
grinding in a ball mill, followed by a tube mill, concentrating on a series 
of Ferraris-type tables, followed by classifying in hydraulic classifiers. 
The concentrates are de-watered in a vacuum filter, dried, and then pass 
to polishing rolls. (For complete flow sheet of mill, see p. 87). The 
recovery is stated to be 65-70 per cent of the graphite in the ore. 1 

Power is furnished by a 160 H.P. Diesel oil engine, using crude oil. 

Twelve men are employed in the mill and about 25 outside. 

The property lies 3 miles east of Buckingham. 
References : — 

Reports of the Department of Mines, Province of Quebec, 1912 to date. 

Monograph on Graphite, Mines Branch, 1907, p. 37. 

Range IV, lot 8 Nj. — Good showings of plumbago and flake graphite 
are reported to occur on this property, which was taken up in 1916 by 
J. E. Hardman, 107 St. James Street, Montreal. Only work of a pros- 
pecting nature has been carried out. 

1 Note:— This mill is at the present time being remodelled for Callow pneumatic oil flotation 



50 

Plumbago, as well as disseminated flake graphite, is stated to occur 
also, on the adjoining lot 8 S §, in range V. 

Range V, lots 1 3 2, and 3. — Known as the Bell mine, and owned by the 
Bell Graphite Company, Friar House, New Broad Street, London, E.C. 
Work was commenced here in 1906 by the present owners, who developed 
a bed of disseminated flake ore on lot 2 W| and erected a mill. Mining 
operations were continued till the end of 1912, and a considerable tonnage 
of ore was run through the mill. Since 1912 the property has lain idle. 

The workings are confined to the escarpment which forms the northerly 
termination of the small plateau on which the workings of the New Quebec 
Graphite Company are situated. In the face of this bluff, a series of over- 
lying, short drifts have been run in on a 12-foot ore-body having a northerly 
trend and a dip of 60° to the west. The ore-body is a graphitic, calcareous 
band enclosed in gneiss, and can be traced for some distance up the slope. 
The best ore is stated to have been found in a winze at the base of the hill, 
from which point good showings are said to have been found on the northerly 
extension of the ore-body, below the present workings. The ore-body has 
been stoped out from the different drifts, leaving supporting pillars. The 
horizontal distance from the lowest workings at the foot of the hill to a 
point below the limit of work up the slope is 500 feet, and the total distance 
for which the graphitic band has been traced is stated to be 2,000 feet. 
About 3,000 tons of ore have been mined from the above workings, which 
are connected with the mill by a tramway. The lowest drift has been 
carried a distance of 200 feet into the hill. The graphite content of the 
ore is said to have averaged 8 per cent. 

About 30 feet to the east of this ore-body, a small amount of work has 
been carried out on a narrower, parallel graphitic band. 

The property lies 4 miles east of Buckingham village. 

Mill 

The mill consists of a large, 3-story wooden structure, the smaller 
wing of which is the original mill built in 1907, the west section being added 
in 1910. 

The mill system was dry throughout and was modelled along the lines 
shown in the flow sheet on p. 76, concentration of the ore being effected 
by means of alternate crushing between rolls of flour mill type and screen- 
ing. At one stage, experiments were conducted with a patented, cone- 
shaped oil flotation tank, but results were not satisfactory. 

Power was derived from a 400 H.P. compound engine, steam being 
supplied by two 200 H.P. Davey-Paxman boilers. 

Most of the mill equipment still remains in the building, but the latter 
is in bad condition, owing to subsidence of its foundations. 
References : — 

Report of the Department of Mines, Province of Quebec, 1910, p. 63. 

Report on the Mining and Metallurgical Industries of Canada, Mines 
Branch, 1907-8, p. 496. 

Range V, lot 19 S~. — Worked in a small way about the year 1865 by 
Mr. Labouglie. " Lenticular masses of graphite in crystalline limestone," 
as well as small veins of plumbago, occur on this lot (St. Mary mine) as 
well as on the adjoining lot 20. On lot 24 in the same range (St. Louis 
mine), a band of graphite in limestone was worked by the above, several 
pits being sunk and about 50 tons of ore secured. 



51 



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52 

Vennor reports the above properties as long since abandoned when 
visited by him in 1876, and no further work upon them has been done. 
Reference: — 

Geol. Surv. Can., Report of Progress, 1863-6, pp. 23-5; 1876-7, pp. 
309 and 318. 

Range V, lots 20 and 21. — Known as the Dominion mine. This mine 
was opened in 1910 by the Dominion Graphite Company, of Toronto, who 
erected a large mill on lot 21 in 1912 and conducted mining and milling 
operations for about six months, when the Company went into liquidation. 
In 1916 and 1917 mine and mill were operated under option by Plumbago 
Syndicate, 1104 Excelsior Life Building, Toronto. The mill was closed 
down during the greater part of 1918, pending the installation of an experi- 
mental, Callow oil flotation unit, but before the process had been properly 
tried out, the mill was destroyed by fire. 

This property w as one of the best equipped mines in the district, but it 
would appear that the plant erected was out of all proportion to the amount 
of ore available and that lack of ore contributed to the failure of opera- 
tions. 

The principal workings lie on a low ridge, on the side of which the mill 
was erected. The latter was connected with the main pit by 1,000 feet of 
tramway, the ore being hauled by locomotive. The principal opening is a 
large open pit on the line between lots 20 and 21. This pit (Lime pit) 
measures 150X80 feet and is 75 feet deep. Practically all the ore taken 
off these lots was obtained from this opening, which follows irregular bodies 
of graphitic limestone. At this point, a body of limestone appears to have 
been caught up in a large mass of gabbro, and the graphite follows the 
approximate contact of this rock with the limestone. Graphite is found 
to a lesser extent, also, disseminated through the mass of the limestone, as 
well as along joints and seams in it, and in smaller amount in the igneous 
rock. The latter forms a body of considerable size, and appears to have 
disrupted the limestone, with the result that masses of limestone occur 
separated by " horses " of gabbro. 

Other small, surface pits exist on the above lots, but have yielded 
comparatively little ore. The Plumbago Syndicate obtained most of its 
ore from what is known as the Stewart pit, on lot 23 in the same range, 
and from the Hogg lot, 23 in range IV. At the former, two small surface 
pits have been opened on a promising body of ore. The deposit lies rather 
flatly and is capped where opened up by 10 feet of limestone. The ore 
consists of banded graphitic limestone, and the deposit, though measuring 
only a few feet in thickness, appears to be well defined. On lot 23, range 
IV, an open cut measuring 100X25 feet was worked in 1917, a well defined 
band of flake ore, occurring along the contact of gneiss with pegmatite, 
being exploited to a depth of 25 feet. The occurrence here is charac- 
terized by flake of phenomenal size, individuals over 5 inches in diameter 
being found. 

Mill. 

The mill, situated on lot 21, was a large, wooden building erected at 
the foot of the ridge on which the main pit is situated. The mill system 
was dry throughout, and was modelled on the usual lines of Canadian dry 
practice (see pp. 74-8). The ore, trammed from the mine, was dumped into 
pockets from which it was drawn into cars and taken up an inclined skipway 
to the kilns (Plate XXVIII). The latter were fired with wood. 



53 

Power was furnished by one 450 H.P. Goldie-McCulloch engine, 
supplied by three 150 H.P. boilers. The actual power consumption in the 
mill was stated to be 225 H.P. Coal was used for firing the boilers, the 
daily consumption being 12 tons. The mill capacity was 60 tons of ore 
per day. 
References : — 

Geol. Surv. Can., Summary Report, 1911, p. 284; Guide Book No. 3, 
International Geological Congress, 1913, p. 105. (Contains a geological 
map, showing the relations of the associated rocks at this mine.) 

Report of the Department of Mines, Province of Quebec, 1917, p. 57. 

Range V, lot 27. — Worked about 1870 by West and Company, who 
shipped " twenty barrels of pure graphite." 1 
Reference : — 

^eol. Surv. Can., Report of Progress, 1873-4, p. 141. 

Range VI, lot 27. — Worked by Messrs. Pugh and Weart in a small 
way about the year 1872. A considerable amount of graphite is stated 1 to 
have been taken from a 4-foot vein of plumbago, upon which a pit 40 feet 
deep was sunk, in addition to an open cut 60 feet in length. This lot is 
stated to have yielded 200 barrels of pure, lump plumbago. Vennor reports 
this mine as abandoned when visited in 1876. All the graphite shipped 
from this lot was in a hand cobbed state. 

The above also owned lot 26 NJ in range V, lots 25 and 26 in range 
VI, and lots 25 S§, 26 Si, and 28 in range VIL Most of the ore mined 
came off lots 25 and 26 in range VI. 

In 1891, the property was more actively exploited by S. J. Weart, of 
Jersey City, who erected a mill on lot 25 in range VI. The mill system is 
described as " separating by air currents and the bolting of the crushed 
and powdered material," 2 the ore being first dried in a kiln. This mill 
apparently represents the first application of dry. concentrating methods 
to graphite in Canada. The graphite refined in this- mill was shipped to 
the Weart plant in Jersey City, where it was used in the manufacture of 
self-lubricating bearings. The mine and mill were operated intermittently 
by the above up till 1895, when the property was leased by the Buckingham 
Company. The latter continued intermittent operations until 1903, since 
when no work has been conducted. The mill was subsequently destroyed 
by fire in 1910. The workings comprise ten main pits, all open-cast: 
these are described in detail in the reference below. 3 In one of the larger 
pits, a vein of plumbago measuring 18 inches at the surface was followed 
to a depth of 70 feet, where it split up into a number of narrow stringers. 
This vein occurs in gneiss, adjacent to a pegmatite mass. In a second pit, 
which has yielded most of the ore taken off the property and is 85 feet long, 
small veinlets of plumbago traverse a band of gneiss carrying disseminated 
flake. The graphitic zone here, also, occurs at the contact of the gneiss 
with pegmatite. 

The property lies 7 miles from Buckingham, and is owned by Spencer 
Weart, 273J Washington Street, Jersey City, N.J. 
References : — 

Geol. Surv. Can., Report of Progress, 1873-4, p. 143, and 1876-7, pp. 
309 and 315; 2 Annual Report, Vol. V, 1890-1, p. 72 SS; 3 Annual Report, 
Vol. X, 1897, p. 68 S. 

Report of the Commissioner of Colonization and Mines of the Province 
of Quebec, 1896-7, p. 93; Reports of the Department of Mines, Province of 
Quebec, 1899-1903. 



54 

Range VI, lot 28. — North American mine. This property was worked 
between 1870 and 1872 by the Canada Plumbago Company, 450 tons of 
refined graphite being produced. In 1875, the holdings of the above were 
taken over by the Montreal Plumbago Mining Company, and in the same 
year the refinery was destroyed by fire and the property abandoned, 
vennor states that both plumbago and beds of disseminated flake occur on 
this lot, the most important of the latter measuring 7 feet in thickness. 
This bed was worked by an open cut 350 feet long and 25 feet wide, and 
later two small shafts were sunk in the bottom of this pit 200 feet apart 
and 30 feet deep. A 70-foot shaft was also sunk on the principal vein of 
plumbago. The crude ore from these workings was shot down the hill into 
scows, which carried it across Twin lake to the Company's mill, situated 
on lot 28 in range V. This mill was erected in 1867, and treated the ore by 
the stamp and buddle system. 

From 1873 to 1875 the only work carried on at this mill was the manu- 
facture of stove polish from stock. 

The Company also owned lot 23 NJ in range V, as well as lots 1, 2, 
and 3 SJ in range X of the adjoining township of Templeton. 

In 1895, the holdings were taken over by the North American Graphite 
Company, who erected a new mill on lot 28 in range VI, modelled on the 
wet concentration system, employing buddies. The mill equipment, as 
described by Obalski, 2 comprised a crusher, battery of ten stamps, cyclone 
grinder, four buddies, rotary dryer and two burrstones, as well as the neces- 
sary screens, etc. The mill capacity was 15 tons of ore per day, and the 
recovery 60 per cent. 

The workings on this property are extensive, and comprise a number 
of surface pits as well as drifts carried into the hill rising between the mill 
and Twin lake. There are eight main openings, which are described in 
detail in the accompanying reference. 1 From the exposures in the various 
pits, there appears to be a series of parallel graphitic bands occurring in a 
belt about 300 feet wide and extending for a distance of some 2,000 feet. 
The largest opening is a drift run 300 feet into the hill just south of the 
mill. Two shafts have been sunk on this hill to meet the drift, which fol- 
lows a band of graphite dipping 60° east. The ore-body is stated to attain 
a maximum width of 10 feet. The other workings lie to the south of the 
above drift, and have been opened on graphite bands having the same 
general direction as that worked near the mill. All the pits are connected 
by a tramway with the drying kiln, situated close to the mill building. 

The above Company continued operations intermittently until 1901. 
In 1904, the Anglo-Canadian Graphite Syndicate acquired the property, 
and remodelled the mill, but went out of business after a few years of 
intermittent work. 

In 1910, the Buckingham Graphite Company, who are the present 
owners, took over the mine and mill, and operated both for the greater 
part of the year. The mill process was dry throughout and in a general 
way similar to that described on pp. 74-8. The capacity of the mill was 60 
tons of ore per 24 hours. After operating for two years, the Company 
abandoned work and the property has since lain idle. Some of the mill 
machinery has since been removed, and the building itself is in a dilapi- 
dated condition. 

The mine lies 8 miles west of Buckingham. 



55 

References : — 

Geol. Surv. Can., Report of Progress, 1876-7, pp. 309 and 316; Annual 
Report, Vol. IX, 1896, p. 54 S; Annual Report, Vol. X, 1897, p. 66 S; 
Monograph on Graphite, Mines Branch, 1907, p. 31. 

2 Report of the Commissioner of Colonization and Mines of the Prov- 
ince of Quebec, 1896-7, p. 93; Report of Department of Mines, Province 
of Quebec, 1910, p. 62. 

Range VII, lots 21 Si, 22, and 27 Si. — These lots were taken up in 
1875 by the Buckingham Company. Vennor 1 states that "asa source 
of pure lump plumbago, perhaps there are few others that can equal this 
location." Beds of disseminated flake also occur on these lots. 

In addition the Company owned lots 15 NJ, 16 NJ, 22 and 23 Si 
in range VI. On lot 23, a number of beds of disseminated flake occur, as 
well as a 20-foot pegmatite dike carrying plumbago. The holdings of the 
Company also embraced lots 24 and 27 in range V, and lot 24 in range IV. 

Very little is recorded as to the operations of the above Company, and 
little work appears to have been carried out. 
Reference * — 

Geol. Surv. Can., Report of Progress, 1876-7, pp. 312 and 318. 

Range VIII, lots 20 and 21 . — Known as the Walker mine, and opened 
in 1876 by the Dominion of Canada Plumbago Company, who erected a 
mill on the adjoining lot 19, which was connected with the mine by 1,000 
feet of tramway. Vennor 1 describes the graphite as occurring on lot 20 in 
a 5-foot bed of disseminated flake, and on lot 21 in irregular veins, ranging 
up to 18 inches in width. A great number of these veins occur on lots 21 
in both the seventh and eighth ranges, but the country rock being in many 
cases of a pegmatitic character and the veins generally narrow, most of the 
work performed by this Company was on the bed of flake ore on lot 20. 
A 9-inch vein of columnar or fibrous plumbago occurs on lot 21 in range 
VIII, on the contact of a mass of pegmatite with crystalline limestone. 
The mineral is very pure and has been pronounced equal in every way to 
the best Ceylon plumbago. 

The method of concentrating the flake ore was by buddies, and crush- 
ing was carried out by a battery of 20 stamps. Stove polish was manu- 
factured at the mill from the lower grades of product. 

The Company also owned the adjoining lots to the south, lots 21 NJ, 
23, and 24 in the seventh range, but carried out little work here. 

After lying idle for a number of years, the property was taken over by 
W. H. Walker, of Ottawa, in 1886, and in 1889, 450 tons of refined graphite 
of various grades were produced. Previous to this time, about 100 tons of 
vein graphite are estimated to have been taken off the various lots com- 
prising the property. 

The mill system in 1889, as described by Obalski, 3 consisted of two 
batteries of 10 stamps, 8 buddies, dryer, and 3 sets of burrstones, in addition 
to blowers, mixers, and screens. The mill was run by one 100 H.P. engine, 
and had a capacity of 20 tons of ore per 24 hours. The ore was estimated 
to run 25 per cent graphite, and the mill achieved a 60 per cent recovery, 
or 3 tons of product per day. 

After some intermittent work between 1890 and 1896, operations 
ceased until 1906, when the Buckingham Graphite Company partially 
remodelled the mill, installing a dry process of concentration, and mined 
some ore. This represents the last work on the property. 

67945—5 



56 




Fig. 8. Plan of workings, etc., at Walker mine, township of Buckingham, Que. Openings 
1-5 are in flake graphite; 6-8 in plumbago. 

The dry process installed was briefly as follows: the kiln-dried ore was 
passed through a jaw crusher, followed by a Gates gyratory crusher and 
heavy rolls, then to a vibramotor sizer, the oversize from which went to 
rolls and trommels and the fines to Hooper dry tables. The fines from 
the trommels went to waste, and the overs to burrstones. The burred 
product was screened, the fines going to waste, and the overs constituting 
the finished product. 

The workings comprise over 30 pits, scattered over the above lots, 
and most of them small surface openings. The main pit is a drift carried 
75 feet into the side of a low ridge near the mill. This drift has been 
stoped out to form a chamber 75 feet long, 15 feet wide and 25 feet high, 
and from it most of the ore treated at the mill has been obtained. The 
other workings are described in detail in the reference below. 2 



57 

The mine is at present owned by M. P. Davis, 285 Charlotte St., 
Ottawa. The lots comprising the property at the present time are the 
following: range VII, 19 N|, 21 NJ, 23, and 24; range VIII, 19 SJ, 
20 S|, and 21 SJ; range IX, 19 Si and 21. 

The mill, which is a 3-story, wooden structure, is in a dilapidated 
condition, and most of the machinery has been removed. 

The property lies 6 miles northwest of Buckingham. 
References : — 

Geol. Surv. Can., x Report of Progress, 1876-7, p. 311; Annual Report, 
Vol. V, p. 73S; 2 Annual Report, Vol. X, 1897, p. 70S; Vol. XII, 1899, Part 
O, pp. 66-73; Summary Report, 1911, p. 283; Guide Book No. 3, Inter- 
national Geological Congress, 1913, p. 101. 

Report of the Commissioner of Crown Lands of the Province of 
Quebec, 1889, p. 95. 3 Mines and Minerals of the Province of Quebec, 
1889-90, p. 89. 

Report on the Mining and Metallurgical Industries of Canada, 1907-8, 
Mines Branch, p. 496; Monograph on Graphite, Mines Branch, 1907, p. 35. 

Range IX, lot 12 N \; range X, lots 12C, 13B, U+B and C, 15B, 17 A 
and B. — Peerless or Diamond mine. 

Work was commenced on lot 14, range X, in 1906, by the Diamond 
Graphite Company, of Rochester, N.Y., who, besides mining a small 
quantity of ore, proceeded with the erection of a mill, and turned out some 
refined graphite during 1907. The mill was modelled on the dry con- 
centrating system, and had a daily capacity of 100 tons of ore. 

In 1910, the property was taken over by the Peerless Graphite Com- 
pany, of Rochester, who, however, did not carry out any mining, finally 
selling out in 1917 to Messrs. Earle and Jacobs. The latter worked only 
a short time, ownership then passing to the Consolidated Graphite Mining 
and Milling Company, of Nashville, Tennessee, who are the present owners. 

A few small openings exist on the mill lot, above the drying kiln, and 
are connected with the latter by tramway. Most of the ore put through 
the mill, however, was taken off lot 12 in range IX, distant \ mile from the 
mill, and from -what is known as the Gorman property in range VII. At 
the first-named locality, a six-foot, flake ore-body has been worked by an 
open pit 100 feet long and 70 feet deep. This ore is stated to average 8 
per cent of graphite. 

The Peerless Graphite Company added to the existent mill equipment 
by installing a Sutton, Steele and Steele electrostatic separator for final 
treatment of the flake. This machine, it is claimed, successfully eliminates 
any mica that is mixed with the graphite. 

The mill has recently been equipped with Callow oil flotation cells. 
Using this method of concentrating, a quantity of graphite was 
recovered during 1919 from old crucibles shipped in from Montreal and 
Lachine steel works. The product made is reported to be of good quality, 
though the flakes are inclined to be thinner and lighter than the natural 
article. 
References : — 

Report of the Department of Mines, Province of Quebec, 1910, p. 64. ' 

Report on the Mining and Metallurgical Industries of Canada, 1907-8, 
Mines Branch, p. 497; Monograph on Graphite, Mines Branch, 1907, p. 35. 

Range IX, lot 15B. — Stripping operations, carried out on this lot in 
1917, disclosed a body of graphitic gneiss and limestone extending for a 
distance of 1,000 feet. The graphite occurs in several narrow bands, 

67945— 5 i 



58 

which are found at irregular intervals in a zone having a width of about 
100 feet. 

The property lies alongside the road on the west bank of the Lievre 
river, and is 5 miles north of Buckingham. The owner is Dr. Cuminings, 
of Buckingham. 

Range X, lot 13. — Worked in 1875 by Mr. Miller, who took out some 
300 tons of disseminated flake ore. 

The adjoining lots, 12 and 14 in the same range, were worked in a small 
way in 1892 by J. Claxton, who shipped a trial consignment of crude ore, 
said to run 20 per cent graphite, to England. 
Reference : — 

Geol. Surv. Can., Report of Progress, 1876-7, p. 310. 

Township of Lochaber. 

Earige VIII, lot 23, and range XII, lot 23. — On this property is the 
earliest worked flake graphite deposit in Canada, operations having been 
commenced about the year 1864 by the Lochaber Plumbago Mining Com- 
pany, of Boston. Little is recorded of the mining operations, the principal 
reports on the work done being those given in the references below. Accord- 
ing to these accounts, the ore mined and milled would appear to have been 
both of the disseminated flake and vein types. On lot 23 in range VIII, 
the occurrence is described as a number of irregular veins of graphite in 
crystalline limestone bordering a pegmatite dike. The graphitic zone was 
30 feet wide and was exploited by a pit 40 feet deep, from which 600 tons 
of ore were taken. 

The occurrence on lot 23 in range XII consisted of a 10-foot band of 
flake graphite disseminated in limestone. The ore was stated to run 20 
per cent of graphite. The bed lay fairlv flat and was worked by a 30-foot 
drift. 

The ore from these occurrences was refined in the Company's mill 
erected on the Blanche river, on lot 28 in range X. Concentration was 
effected by means of buddies, the ore being first crushed by stamps, and 
the concentrates were refined by burring and screening. 

The Company also owned the mining rights on lots 24 and 25 in 
range XI, and lot 21 in range X, on which properties promising showings of 
graphite were reported to occur. 

Both mines and mill of this Company were reported by Vennor in 
1876 as having been idle since 1868, and nothing further has ever been 
done. 
References * — 

Geol. Surv. Can., Report of Progress, 1863-6, p. 22; 1876-7, pp. 309 
and 319. 

HULL COUNTY. 
Township of Low. 

Range III, lots 17-20 — Some prospecting was carried out on lot IS 
during 1916-17 by the Gatineau Graphite Company, of Ottawa. In 
1918-19, the same lot was diamond drilled by a Toronto syndicate, who 
put down three holes to a depth of about 100 feet, and opened up a number 
of small surface pits. Results were not satisfactory, however, and work 
was abandoned. The present owners are Messrs. McLean and Fitzsimons, 
14 Metcalfe Street, Ottawa. 



59 

The graphite here is mainly of the plumbago variety, with a certain 
proportion of large flake scattered through the rock adjacent to the 
plumbago stringers. The occurrence consists of irregular bands of 
plumbago developed along the contact of gabbro dikes intruded 
into crystalline limestone. Along the borders of such dikes, irregular 
masses of plumbago occur, and the mineral is also found as narrow veins 
traversing the gabbro itself. The latter also contains aggregates of 
disseminated large flake. The plumbago is mostly of the foliated type, 
no columnar or fibrous material being noticed. The maximum width 
of the veins exposed is about 6 inches. (See Plates II and V.) 

While a proportion of the plumbago may be cobbed to form a market- 
able product, it would be necessary to mill the greater portion of the ore, 
since much of the graphite contains an intimate admixture of foreign 
mineral matter, chiefly calcite, feldspar and various lime silicates. As far 
as could be seen in the limited number of exposures, the limestone adjacent 
to the dikes is not impregnated with graphite for more than a short distance 
from the contacts. 

While of generally similar type to the occurrences in Amherst and 
Grenville townships to the east, this deposit differs from these in that 
there has been a less intensive degree Of metamorphism exerted by the 
intrusive rock upon the limestone, with the result that there has been 
no development of a zone consisting of an aggregate of very coarsely 
crystallized lime silicates mixed with graphite, as at the above mines. 

Graphite outcrops have been found over a considerable area on these 
lots. 

The property lies 3 miles from Low station, on the Gatineau valley 
branch of the Canadian Pacific railway. 

A shipment of about 30 tons of ore obtained from surface workings 
on this property was sent to the Mines Branch Ore Dressing Laboratory 
for cleaning. The material, as received, consisted of three lots of different 
grades, as follows: — 

Lot No. 1 (High Grade). 

3,306 pounds 38- 18 per cent carbon. 

Lot No. 2 (Medium Grade). 

8,092 pounds 18- 10 per cent carbon. 

Lot No. 3 (Low Grade). 
48,874 pounds 4-33 per cent carbon. 

The high grade material was broken to 1" and screened on \" , the 
oversize being hand picked. The product thus secured assayed 79-2 
per cent carbon. 

The discard and the throughs from screening were crushed to \" , 
oiled and passed over a Wilfley table. The concentrates assayed 77-1 per 
cent carbon. 

The object of the above procedure was to determine whether high 
carbon products of coarse size (comparable to Ceylon "lump" and "chip") 
were obtainable from this class of ore by such methods. While the pro- 
ducts secured were fairly satisfactory from the point of view of carbon 
content, the methods could hardly be employed commercially on account 
of the expense involved. 

The low grade material was treated by the Callow oil flotation system. 
It was ground in a Hardinge ball mill, the discharge from which passed 
to a launder classifier, the oversize being returned to the mill. The first 



60 

concentrate from the notation cells ran 71-6 per cent carbon. They were 
re-ground in the Hardinge mill and re-floated; by this means, the carbon 
content was brought up to 80 per cent. 

The medium grade material, together with the table tailings from 
lot No. 1, was also cleaned on the Callow machine, a first concentrate 
running 80 per cent carbon being obtained. 

Finally, the whole of the concentrates, both from the Callow machine 
and the Wilfley table, together with the hand picked material, was run 
through the Callow circuit, and a final concentrate was secured, for which 
the following values were obtained: — 



Pounds. 


Size. 


Per cent 


Carbon, 






carbon. 


pounds. 


683 


+ 50 mesh 


95-05 


649-19 


625 


+ 62 " 


91-20 


570-00 


169 


+ 74 " 


89-75 


151-68 


637 


+ 86 " 


90-30 


575-21 


611 


+ 109 " 


87-40 


534-01 


362 


+125 " 


88-60 


320-73 


363 


+150 ." 


87-10 


316-17 


116 


+200 " 


85-20 


98-83 


452 


-200 " 


85-05 


384-43 


4,018 


3,600-25 



The percentage of recovery was 76-41, and the average carbon content 
of the different sizes of product, 89 • 6 per cent. 

Range III, lot Ifi. — A deposit of plumbago, resembling in a general 
way that found on lots 17-20, has been exposed by stripping operations, 
carried out by William Evans, of Low, in 1917. The graphite occurs 
in a 12-inch seam in crystalline limestone, and is mixed with quartz. 
The adjacent limestone carries no appreciable amount of disseminated 
flake. 

Maniwaki Indian Reserve. 

Gatineau jront, lot 10.- — A belt of graphitic limestone crosses this lot. 
The limestone is bordered to the east by a mass of igneous rock of granitic 
t}^pe, and is graphitic for a distance of some 500 feet from the contact. 
There is no exceptional development of graphite at the actual contact, 
and the graphite content of the limestone as a whole is low, probably 
not exceeding 2 or 3 per cent. Certain rich zones, however, carrying 
a large proportion of very large flake, might possibly prove of economic 
value. 

ADDITIONAL GRAPHITE LOCALITIES IN QUEBEC. 

In the township of Lochaber, Labelle county, excellent showings 
of disseminated flake graphite are reported to occur on a number of lots 
in the vicinity of the holdings of the old Lochaber Plumbago Mining 
Company (see p. 58). These occurrences have not been examined by the 
writer, but by several competent authorities the outcrops are regarded 
as some of the most promising in the district. A small amount of surface 
work has been carried out on some of the lots at different times, and the 
exposures indicate the presence of several parallel ore-bodies, having 
widths of from 3 to 20 feet. The average graphite content in samples of 



61 

the surface ore is stated to be 10-15 per cent. The above properties 
comprise the following lots: — 

Range XI, lots 21, 22, and 23, N i's; range XII, lot 22.— Owned by 

H. Dickson, 70 Gloucester Street, Ottawa. 
Range XI, lot 21, S J. — Owned by Rev. Father Chatelain, Bucking- 
ham, Que. 
Range X, lot 20;. range XI, lots 17 and 18, N i's, 23 S J.— Owned by 

Hon. W. C. Edwards, Sussex Street, Ottawa. 
Other localities from which graphite has been recorded, but which 
are not known to have been actively worked, are: — 

Argenteuil countv, township of Grenville, IV, 8. (Rep. Comm. Col. 

and Mines, Prov. Que., 1896-7, p. 93.) 
Hull county, township of Cameron, IV, 47. 
Hull county, township of Hincks, XIV, 47. (G.S.C., 1892-3, p. 

63 S.) 
Hull county, township of Hull, XI, 9. (Rep. Comm. Crown Lands, 

Prov. Que., 1892, p. 80.) 
Hull county, township of Northfield, B, 28-30. 
Hull county, township of Wakefield, I, 7. 
Hull county, township of Blake, VIII, 24. 
Labelle county, township of Portland West, III, 11. (Rep. Comm. 

Crown Lands, Prov. Que., 1892, p. 80.) 

BAFFIN ISLAND. 



Graphite has been recorded from time to time as being found at various 
localities on Baffin island. Thus, R. Bell records 1 the receiving of speci- 
mens at Black Lead island, Cumberland Sound, in 1897, and in 1885 from 
Eskimos at Ashe inlet, on Big island. 2 In the latter case, the specimens 



^^^ * \. 




1 


White crystalline limestone h 










■^^ 8 added limestone carrying 
.Vf disseminated particles of 


Greatest concentration of 


« '• '\;'.' •! ,r •' .' »' • 


plumbago occurs on this 




~TrA graphite 


side of dike 


» , k 1< ' ■' ."".*"■.«( 


\* l\.'.\v^' ;''*);! 




~* ' * iV'.' , *. , V'': 






?L»- * %'•'• • 




Quartz dike with disseminated 


~~~^ST* r V-^jL^J. 


V" '•' •' ■ * .'A 


particles of graphite 


\ ' ' % " ■ r 


.*•'( '•!:<• ' '1. • .V 



Fig 



9. Sketch showing occurrence of plumbago, at the Joker claim, Lake harbour, 
Baffin island. (J. Maltby.) 



are said to have come from a point east of Big island, and were possibly 
found in the neighbourhood of Lake harbour (see above). A. P. Low, also, 
mentions 3 veins of graphite occurring south of Port Burwell, on the east 
shore of Ungava bay, and near Cape Wolstenholme, as well as on the east 
side of Baffin island. 



62 

In 1916, the Hudson Bay Company commenced the development of a * 
graphite deposit near Lake harbour, on the south shore of Baffin island, 
behind Big island, and in 1917 and 1918 shipped out a small tonnage. The 
graphite is of crystalline or vein variety, and requires only to be hand 
cobbed in order to fit it for market. The veins, of which several have been 
worked, occur in crystalline limestone, probably of Grenville age, on its 
contact with intrusive, quartz dikes. The accompanying sketch of the 
occurrence at the " Joker " claim, was kindly furnished by T. J. Maltby, 
the Company's engineer in charge of mining operations. 

The graphite secured was shipped to a crucible firm, who report its 
quality as equal to the best grade of Ceylon plumbago. 
References : — 

^eol. Surv. Can., Ann. Rep., 1898, Vol. XI, p. 20M. 2 Rep. Prog. ; 
1882-5, p. 24DD. 

3 Cruise of the Neptune, Dept. of Marine and Fisheries, 1906, p. 245. 



63 



CHAPTER V. 

CONCENTRATING AND REFINING OF GRAPHITE. 

As a general thing, the natural graphites, whether of the plumbago or 
flake type, as well as, in some cases also, the amorphous variety, require to 
be subjected to some cleaning process before they can be utilized in the 
various industries. 

PLUMBAGO. 

In the case of plumbago, the amount of mineral impurities present is 
generally so low that sufficient purity can be attained by a system of hand 
picking and cobbing of the ore. The best grades of Ceylon plumbago, 
prepared for the market by such means, run well over 90 per cent carbon. 
At the Ceylon mines, the ore is first roughly picked over, the attached 
gangue reduced to 5 or 10 per cent, and then shipped to the curing or 
dressing compounds at the coast. Here, the larger pieces are picked out, 
and the remainder sized by means of stationary, inclined screens. The 
large pieces are broken up with small hatchets, and the impurities removed 
as far as possible by picking; the cleaned graphite then being similarly 
sized. The larger sizes are placed on pieces of wet sacking, where they are 
again picked over, and rubbed up by hand, then polished by being rubbed 
on a fine mesh screen placed flat on the ground. These larger sizes, which 
may measure up to 1 inch across, are graded as " ordinary lump," and 
" medium lump," and command the highest prices. The graphite that 
passes through the screens is graded according to size into " chip " and 
" dust." 

The lower grade material is pulverized with wooden mauls or beaters, 
and is then placed on sacking, and sorted into various grades by hand. In 
some cases, the cleaning of this material is effected by washing it in saucer- 
shaped baskets, which are moved by hand with a " panning " motion 
beneath the surface of water. By this means the graphite is thrown off 
into the water, while the particles of gangue remain in the basket. The 
graphite is afterwards shovelled out and spread on drying floors, where it 
is dried by sun heat. The dried graphite is then winnowed by being placed 
in shallow baskets and thrown into the air, the heavier particles falling back 
into the basket, while the fine dust is blown forward and falls to the ground. 
These products are known respectively as " dust " and " flying dust." 

Considerable attention is paid to the blending of Ceylon graphite: 
by which is meant the mixing of the product of various mines. The three 
main grades — lump, chip, and dust — are further classified into several sub- 
grades, according to quality. 

Such a procedure as outlined above is, of course, only practicable in 
countries where cheap native labour is obtainable. In the case of deposits 
of plumbago on this continent, the usual method of treating the ore ha a 
been to break it by hand into pieces of medium size, cobbing out the gangue, 
the resulting waste being discarded, or, in the event of there being a mill 
near, run through the latter. 

AMORPHOUS GRAPHITE. 

Amorphous graphites vary so widely in their carbon content and 
physical character, that the treatment to be undergone, depends, largely, 



64 

on the use to which the material can be put. Mexican graphite, for 
instance, is of exceptionally high grade (86 per cent), and for this reason, 
and on account of its extreme softness, is well adapted for such purposes as 
pencils, lubricants, etc. Rhode Island graphite, on the other hand, is 
impure, and somewhat hard, for which reason it is employed almost exclu- 
sively in low grade foundry facings. Other impure, amorphous graphites, 
carrying 35 to 50 per cent of graphite, can be utilized in paints, stove 
polish, etc. For such purposes a high carbon content is not essential, and 
the presence of a considerable proportion of clayey matter is not prejudicial. 

As it is practically impossible to refine the amorphous graphites 
mechanically, owing to the intimate association of graphite and impurities, 
much depends on the nature of the impurities as to what use the graphite 
can be put to. Practically, all amorphous graphite deposits represent 
either graphitized coal seams, or metamorphosed carbonaceous slates or 
shales, so that a wide diversity of composition is exhibited by the ores from 
different localities. Styrian graphite, for instance, while amorphous, 
contains no sulphur, and yields an infusible ash; for which reason it is said 
to have been found to be well adapted for crucible manufacture 1 , while the 
same holds good to a certain extent for the Pinerolo deposits, in Italy. In 
the latter district, a number of dressing plants have been established. 

As far as the writer is aware, no refining of amorphous graphite is 
practised on the American continent, the ore being merely hand picked at 
the mines, and then subjected to a fine grinding and air flotation process. 

One firm having large graphitic slate deposits in Michigan — the ore 
from which averages 35 per cent graphite — subjects the material to the 
following process: the ore passes first to two jaw crushers, a coarse and a 
fine, then to a Raymond automatic pulverizer; the pulverized ore is then 
dried on trays in a chamber heated by steam coils, and when thoroughly 
dry is fed to two continuous feed and discharge tube mills. These are 
run in conjunction with two Raymond air separators and dust collectors. 
The fines from the former run about 350 mesh, and are employed principally 
as paint stock; the coarse returns to the tube mills for further grinding. 

The United States Graphite Company treat large quantities of Mexican 
amorphous graphite at their plant at Saginaw, Mich. The run-of-mine ore 
averages 80-85 per cent graphite, and is screened to f inch at the mine. 
At the mill it is screened to J inch; the oversize, which commonly runs 
lower in graphite than the fines, being ground in a Raymond roller mill 
(Raymond Brothers Impact Pulverizer Company, Chicago) and made up 
into foundry facings. The fines are ground in continuous feed and dis- 
charge tube mills, and the product of the latter is floated in Raymond air 
separators (200 mesh). The air-floated graphite is employed in lubricating 
greases, stove polish, paints, electrotyping, and boiler graphite, and is in 
special demand for pencil manufacture. 

In Fig. 10 is shown a grinding installation specially designed for the 
fine grinding of graphite (Raymond Bros., Chicago). 

FLAKE GRAPHITE. 

The extraction of flake graphite from its ores, and its preparation for 
the market — more particularly the crucible trade — has always been a 
problem presenting considerable difficulties from both the technical and 
the economic side. This is due in the first place to the fact that the prin- 

1 Dammer und Tietze, Die Nutzbaren Mineralien, Vol. I, p. 65. 



65 



cipal minerals with which flake graphite is usually associated, (quartz, 
calcite, feldspar, and mica), and which commonly form from 75 to 95 per 
cent of the ore, possess specific gravities varying but little from that of 
graphite itself; added to which, one of the most common impurities — 
mica — is of more or less identical form, hardness and toughness, and 
behaves in much the same fashion as the graphite particles at practically 




mjr 



XTU- 



Fig. 10. Installation of Raymond high-side roller-mill equipment for grinding graphite. 

all the stages of mechanical treatment, such as grinding, jigging, tabling, 
screening, etc. Owing to this latter fact, mica is one of the most difficult 
minerals to eliminate by any of the straight mechanical processes; and, 
being a mineral that fuses readily at the temperatures to which crucibles 
are subjected, its presence even in minor amount is highly prejudicial in 
graphite intended for the crucible trade. 

The principal difficulty, however, in connexion with the concentrating 
and refining of flake graphites, is due to the fact that the crucible trade, 
which uses probably about three-fourths of the world's output of graphite, 
demands the best quality, and pays the highest prices, specifier that what 
is known as " No. 1 crucible flake " shall not only possess a high carbon 
content (90 per cent or better), but, in addition, must not exceed a certain 
degree of fineness. The limits usually set in this connexion are 20-90 
mesh; that is, the flakes must pass a 20-mesh screen and be caught on 
90-mesh. It will be readily seen, therefore, that the concentrating and 
refining of flake graphite have, since the inception of the industry, been 
attended with more and greater difficulties than have been encountered in 
possibly any other branch of ore-dressing. Processes have been devised 
which have proved more or less satisfactory in as far as carbon content and 
size of flake were concerned; but such results have almost invariably been 
achieved at the expense of recovery, and frequently, also, by some system of 
re-treatment that rendered operations unprofitable. It is probably not an 
over statement to say that, by any of the concentrating processes hitherto 
employed — at any rate on the American continent — and excepting oil- 
flotation, the average loss of graphite in the tailings has been not less than 
50 per cent of that contained in the ore treated. This has been due to the 
fact that it has always been found practically impossible to free all of the 
flake completely from the gangue without reducing an undue proportion 



66 

of it to powder form, in which state it is unsaleable to the crucible trade. 
Graphite ores vary widely as regards the relative proportions of large-sized 
flake that they carry. In some cases, notably in certain crystalline lime- 
stones, a considerable proportion of the flake is of relatively large size 
(plus 40 mesh) ; but this is discounted by the fact that such flake is often 
brittle and breaks up very readily during grinding of the ore. The schistose 
ores, on the other hand, usually carry flake of a uniformly smaller size, 
though, occasionally, exceptionally large flake is encountered. The flake 
of the schists is, as a general thing, somewhat tougher than that of the lime- 
stones, which enables it to resist destruction better during milling. Some 
schist-ores carry flake possessing very regular, elliptical form, and having 
perceptible thickness. Such flake frees readily on milling without breaking 
up, and yields little dust graphite. In others, the graphite flakes are 
decidedly irregular and break up easily into smaller particles, so that the 
amount of large flake recoverable is relatively small. Where such ores are 
highly siliceous, as is sometimes the case, the graphite is difficult to free, 
and the proportion of dust graphite made during milling may be so high as 
to render operations unprofitable. In Alabama and Pennsylvania, most 
of the ore milled is weathered surface schist, and although of low grade (3 
and 5 per cent graphite content respectively) requires little grinding to 
free the flake. The New York and Canadian graphitic gneisses, on the 
other hand, are weathered for only a short distance down, and most of the 
ore raised is comparatively hard, and requires a considerable amount of 
grinding. For this reason, dry methods of concentration have found 
considerable favour in Canada, owing to the fact that the initial drying of 
the ore in kilns serves also to decrepitate the calcite present, thus rendering 
the rock more friable and easily milled. 

Another problem encountered in exploiting Canadian graphite deposits 
is the not infrequent tendency of the ore to alter its character either in 
depth or along the strike of the ore-body, or both. Such alteration usually 
consists in local variations in the proportion of mica, quartz, calcite, or 
pyrites present in the ore. 

In the upper, weathered portions of graphite deposits, also, a certain 
amount of enrichment due to decomposition of sulphides and solution of 
calcite may frequently be noticed, and the graphite content of such surface 
ore may, therefore, be considerably greater than that of the unweathered 
ore. In addition, Canadian flake graphites usually carry a perceptible 
amount of sulphides (pyrites and pyrrhotite) , and in some cases, quartz 
also, as a sort of skeleton between the laminae of the flakes. These inter- 
grown impurities are impossible to eliminate by mechanical means 
without reducing the graphite to powder, and it is to their presence that 
the relatively large amount of ash often yielded by apparently perfectly 
clean, selected flake is to be attributed. 

Estimates of the graphite content of a deposit, based on analyses of 
surface material, are thus apt to be misleading; and, for the same reason, 
concentrating tests on such material may yield results that lead to erroneous 
conclusions. In the latter connexion, an additional cause of error is liable 
to be found in the fact that the flake in oxidized ore is more readily freed 
from its matrix, and, consequently, a smaller proportion of fines will result 
on milling. For these reasons, analyses and mill tests should always be 



67 

made on fresh, unweathered ore, as only in this way can reliable data be 
secured. 

N^The more important points to be considered in connexion with the 
dressing of flake graphite ores include the following: — 

Character of the ore, and the ratio of large size flake recoverable to 
the total graphite content. Tough, siliceous ores may require prolonged 
grinding in order to free the flake, with the result that much of the latter 
is destroyed ; an undue amount of the graphite recovered being in the form 
of dust. The profitable operation of a dressing plant is essentially depend- 
ent on its production of No. 1 flake, the market for the No. 2 flake and 
dust grades being uncertain, and the prices offered out of all proportion to 
the cost of production; hence it is necessary that a graphite mill, to be 
successful, must recover from each ton of ore treated, sufficient No. 1 flake 
to meet the cost of mining and milling. 

Selection of grinding machines that will free the flake in the ore with 
the production of the minimum amount of fines. This is a matter of 
supreme importance, but which, frequently, has not received the attention 
it demands. Various types of grinders are in present use in the various 
graphite fields, and include chaser mills, ball mills, fine rolls and stamps. 
There is a decided difference of opinion among operators as to the most 
efficient method of grinding, and a type of machine adapted to one class of 
ore will probably not give as good results on another. It would seem 
desirable, therefore, that more experimental work should be done in this 
connexion. 

Graphite ores, even from one and the same district, vary so widely in 
the character of the flake they carry, nature of the associated minerals, 
hardness, graphite content, etc., that it is quite impossible to outline any 
mill method that will even approximately meet all conditions. In the 
following pages are described a number of the systems that have been tried 
out in mills in the Alabama, Pennsylvania, New York, and Canadian 
fields. While a number of the processes enumerated have not proved 
wholly efficient, owing to expense of operation, poor recovery, failure to 
make a clean product, or to a combination of these causes, their salient 
features are given here with the object of outlining what has been attempted 
in the province of graphite ore-dressing. 1 

Concentration by Dry Methods. 

Graphite concentration by dry methods has been more widely adopted 
in Canadian mills than elsewhere; eight plants having been equipped in 
the past along these lines. At the present time, however, all of these mills 
are either idle or have been remodelled along other lines. Dry concentra- 
tion has also been attempted in one Pennsylvania mill, the system followed 
being that of rolls and screens, as in Canadian practice; except that a rotary 
dryer was employed in place of vertical kilns to dry the ore for the crushers. 
It is understood that this mill has since been remodelled for K. and K. oil 
flotation. 

1 To a bulletin entitled Preparation of Crucible Graphite by George D. Dub, issued by the 
Bureau of Mines of the United States, December 1918, the writer desires to make his acknowledg- 
ments for amplification of the data personally secured in the Alabama, Pennsylvania, and New 
York graphite districts, in 1918. Many of the figures depicting apparatus in use in the Alabama 
field are taken wholly or in part from this report. 

A further bulletin, dealing with methods of cleaning Alabama graphite ores, and entitled 
Refining Alabama Flake Graphite for Crucible Use, by F. G. Moses, has also been published 
by the above Bureau (December, 1918). This report contains much data secured in the course of 
experimental work carried out at the Intermountain Station of the Bureau of Mines, at Salt Lake 
City, Utah, with various methods of concentrating and refining Alabama graphite. The bulletin 
came to the writer's attention too late for any of the data contained in it to be utilized in the 
preparation of this report. 



68 

Several mills in Alabama were equipped for dry concentration in 
1917-18, Sutton, Steele and Steele dry tables being used. The majority 
of these mills are believed to have since discarded this system for film or 
some other flotation process. 

In any method of dry concentration of graphite, it is necessary that 
the ore be thoroughly dry before it enters the mill. This preliminary 
drying is usually effected in vertical kilns. The smaller mills use a single 
kiln, but the larger mills, designed to treat 150 to 200 tons of ore per 24 
hours, are equipped with two kilns. These are usually of masonry con- 
struction, though sheet iron is used in some cases. (Plate XXVIII.) 
Wood is employed for fuel, lj to 2 cords being necessary to dry 100 tons^of 
ore. 

In dry concentration, two essentially dissimilar methods have been 
practised. These are: (1) separation of the graphite and gangue on 
pneumatic tables or jigs; and (2) gradual elimination of the more brittle 
gangue constituents by means of a succession of rolls and screens. In 
some mills a combination of both methods is practised. 

PNEUMATIC JIGS. 

One of the first attempts at dry concentration was by means of the 
Krom pneumatic jig (Krom Machine Works, 170 Broadway, New York). 
This machine (see Fig. 11) consists of a swinging door blower B 
with check valves to prevent the downward passage of air, conveying rapid 
pulsations of air into the tubes T, one-half inch wide, of sieve cloth, through 
the sides and tops of which the air passes up through the bed of ore, and 
effects the separation between graphite and the gangue. These gauze 
tubes T are open at the end to the blower, to receive the wind, and on the 




Concentrates 



Gangue 



Fig. 11. Section through Krom pneumatic jig. 



under side to prevent them from choking with fine ore. They are placed 
A> i> f > or \ inch apart, according to the grade of ore to be treated — 
the finer the feed, the closer the tubes are set. The ore is fed through a 
hopper H, passes under the adjustable gate G, and forms the jigging bed. 



69 

Clean graphite is discharged over the adjustable apron C, while the tailings, 
which completely fill the hutch below the tubes T, settle slowly, and are 
discharged by the regulated roller R. The swinging-door blower is actuated 
by a cam on the main shaft, with six projections, which give the downward 
motion through an arm on the shaft; a spring which gives it the quick 
upward pulsation; and an adjustable strap which limits the amount of 
pulsation. Upon the cam is an adjustable crank pin, which serves as a 
pivot for a pawl acting upon a ratchet wheel to drive the discharge roller 
R. The roller, therefore, acts in concert with the blower. The width of 
the bed is four feet. The machine is run with 420 to 750 pulsations per 
minute. It treats from 300 to 600 pounds per hour, using one-eighth horse 
power. The coarsest size claimed as capable of being treated by this 
machine is 6 mesh, and the finest is 140 mesh. This machine is said to 
have given good results, but it needs careful adjustment to the graphite 
content of the ore; any rise or fall in the latter tending to effect a loss of 
graphite or a dirty concentrate respectively. 

Krom jigs are not known to be employed in any graphite mills at the 
present time, either in the United States or Canada. 

Another machine that has been employed in the concentration of 
graphite by the dry method is the Hooper pneumatic concentrator. This 
machine is shown in Plate XXX and Fig. 12. 




Fig. 12. Section through Hooper pneumatic concentrator. 



Richards, in his work on "Ore Dressing", describes the Hooper con- 
centrator as follows : — 

Through 1 the chamber A runs a rectangular diaphragm a. This diaphragm is 
composed of an outer rim of leather, the sides of which are firmly bolted between the upper 
and lower sections of the air chamber. Within the chamber the leather is firmly attached 
to a strong wooden frame, b, which is divided by transverse wooden braces c. Between 
these braces, and attached to them, are two rubber flaps resting upon a sheet of perforated 
metal. The diaphragm is connected to two eccentric boxes, B, in which revolve a fixed 

1 Richards, Ore Dressing, Vol. II, 1903, p. 820. 



70 

eccentric attached to the working shaft C, each eccentric being cased by a loose eccentric 
sleeve, d, which can be adjusted and held by a set screw, e, allowing a throw of | to l\ 
inches. A movement is thus communicated to the diaphragm which discharges at each 
revolution an air blast to the chamber A, which blast then passes through the fixed dia- 
phragm G — also arranged with rubber flaps — and is discharged through the grated sieve, 
g, upon a broadcloth bed, f, stretched over same. Resting upon the broadcloth bed is the 
concentrating top, which consists of two sets of guide strips, running diagonally to each 
other and at angles of 30° to 45° with the side of the frame. The lower set of strips, H, 
are of brass, ■& inch thick, £ to \ inch high, and f to 1^ inches apart, depending upon the 
material to be treated. The upper set of strips, I, called skimmers, run upon, and diagon- 
ally across, the lower set. They are also of brass, -h inch thick, 3| inches high, and f to 
f inch apart. These upper strips terminate 2 inches from the left or discharge side of the 
top for a distance of 23 inches from the discharge end, thus leaving a free discharge channel, 
K, for the concentrates. The concentrating top may be removed from the concentrating 
bed at will. Any desired vertical or lateral inclination of the concentrating bed is obtained 
by means of a universal joint, E, which is held in the desired position by means of two 
clamps situated at opposite sides of same, as shown at h. The maximum inclination 
toward the discharge side is 11°, and that toward the concentrating side 5°; depending 
upon the character of the ore being treated and the mesh to which it has been sized. As a 
general rule the larger the mesh and the heavier the mineral, the greater the inclination in 
both directions. The crushed ore, after being closely sized, is fed from a hopper (not shown) 
placed at the head of the concentrating bed. This hopper is adjustable in position, and 
is provided with small sliding gates, by means of which the flow is adjusted. 

It will be evident from the foregoing that when crushed ore, composed of particles 
of different gravities, is fed upon the concentrating bed, the pulsations through the broad- 
cloth, due to the blasts before described, cause the heavier mineral particles to be thrown 
to the bottom, where they settle down between the lower metal strips and are thus guided 
toward the tailings side of the table, the lighter graphite being thrown to the top where 
it is subjected to successive skimming actions by the upper set of metal strips and thus 
guided in the opposite direction toward the concentrates side of the table. After the bed 
is filled to an even depth of \ to f inch, and the resulting products of concentrates, middlings 
and tailings begin to flow regularly and smoothly over the discharge end of the table, the}' 
are guided to any point of disposition by means of wooden guide strips, F. It is found 
that the various minerals contained in an ore classify according to their specific gravities, 
the heavier mineral, being interrupted in its flow by the side of the concentrating top, is 
spread out in a well defined strip by the action of the upper skimmer, the next heaviest 
taking its place beside it, etc. There is therefore a distinct separation of all the minerals 
should there be sufficient variance in their specific gravity. 

To obtain the best results the ores treated should be below 2 mm. and should be 
closely sized, say through a 20-mesh screen on a 30-mesh, through 30 on 40, 40 on 60, 
60 on 80, 80 on 120 and 120 on 250. Of course, when there is considerable variance between 
the mineral and gangue, close sizing is not so important. The speed of the machine varies 
from 350 revolutions per minute in the case of coarse material to 450 for fine. This 
variation in speed is obtained by means of cone pulleys. The stroke or force of air is varied 
by the length of eccentric throw by adjusting the eccentric sleeves before described. The 
greater the throw of these eccentrics the stronger the air blasts. The heavier the material 
treated the heavier the air blast required. All machines are now supplied with an adjusting 
device by means of which the throw of the eccentrics may be altered at will without stopping 
the machine. The capacity of the machine varies from 9 to 16 tons per day of 24 hours, 
according to the character of ore treated, and the horse-power required varies from \\ 
to 2. 




Tailings-' \ 

Middlings* 



Fig. 13. Sutton, Steele and Steele three-section jig. 

The Hooper table was used formerly on the graphite ores of the 
Buckingham district, Quebec, with what results is not known to the writer. 



71 

Fig. 13 shows the Sutton, Steele and Steele 3-section, dry jig table, 
which has been used in both Alabama and Canadian mills. This table 
has a smooth deck, free of riffles. It is mounted on a shallow wind chest. 

Two 30 ton drying fa/ns 

I 

Gnzz/y. %• CONCENTRATING DEPARTMENT 



7/J 



Throughs 



Overs 
I 



Two whiptap 



/Rolls /40 * 16 "set at %) 



Throughs 

1 

Oeduster 



screws/ /6 mesh) 



Oyers 
I 



Oyers 



fines 



/fo//s/40"*36) 



Two Alewaygo screens {30 mes h) 

Oyers Throughs 

3 section dry table 

, 1 ""I 

Concentrates Middlings Tailings 

4 I I •— 



Thre e cyc/one dust co/ /ectors 
Overs Dust 

Three screens{/00 me sh) 
Overs Throughs 

t — * tzt 



Overs 



Ree//40mesh ) 

Throughs 
Standard dry ta6/e 

I T~ 1 

Concentrates Middlings Tailings 



/o/umetric sizer 



Coarse Medium 

I 1 

c? 3 section dry tab le 3 section dry tabl e 

Cones. Midds. Tails. Cones. M/dds. Tails 

I 



m ' i 



Fine 

Z section dry table 

Cones. Tails. 

L_ 



FINISHING DEPARTMENT 



I 

/fee/ (TOO mesh ) 

Overs Throughs 

I 1 

r?o//s. {9~*36") 



/.k 



Ree/JTOOmesh) 



Overs 



Throughs 

1 



7b waste. 



Suhrstones 
Double reel. (10 and ISO me shj 

I T^ 1 

+100 ~IOO"-/50 +/50 

I I 1 

Af°/ product M°Z product M°3produci 



Fig. 14. Flow sheet showing Sutton, Steele and Steele dry concentration installation, in 

an Alabama graphite mill. 
67945—6 



72 

which is supported on the running gear and connected with a blower, and 
is oscillated lengthwise with a J-inch stroke. The cover of the deck is 
porous, being made of fine-mesh canvas. The running gear rides on springs 
set at an angle, which imparts a slight rise to the deck as it travels forward. 
This motion causes the feed to travel rapidly across the table, and the air 
film, formed on the surface of the deck by the expansion of the air passing 
through the porous cover, stratifies the material. The lighter gravities 
come off the table nearest the feed end, so that the graphite concentrates 
are obtained from what would be the tailings spigot in the case of a metal- 
liferous ore. The machine would not appear to be especially adapted to 
graphite concentration, owing to the relatively slighter difference in specific 
gravity between graphite and the majority of the minerals commonly 
associated with it — more especially mica. This difficulty is claimed to be 
overcome by the use of the volumetric sizer which classifies the feed for the 
tables; but it is doubtful whether this machine can be completely efficient 
on graphite, owing to the difference in shape of the particles to be sized. 



Charge, crude ore 38,427 lbs. 

Moisture 1,644 » 

Total , 36.783 .. 




Tailings 
7.265 



Screen/ess 



/r/ 

Table 



1^ 

N?2 

Table 



Cones. 
1/4 



Tails 
7.209 



Cones. 
100 



Ta//s 
5.029 



1^ 
Al?3 

Tdb/e 



'a? house 
468 



N°4 
Table 



Fines 
Table 



Cones. 
134 



Tails. 
4,380 



Cones. 
144 



Tails. 
4.427 



Cones. 
145 



Tails 
7,130 



AESUME.- 



Concentraies Deduster Fines 248 lbs. Waste 7723 lbs. 



Sizer N? / 1/4- - 


» 


7203 >. 


TV? 2 100 - ■ 


„ 


5029 » 


N? 3 /34 - 


„ 


4380 .. 


A/9 4 144 „ 


„ 


4427 •. 


" Fines 145 - 


" 


7/30 » 


Total 885 - 


3583-8 » 



Recovery. 2 40% 

d// o^er 80 mesh in size 

Fig. 15. Result of test made on 20 tons of graphite ore from Clay county, Alabama, at 
the Denver testing plant of the Sutton, Steele and Steele M. M. and M. Co. 



The accompanying flow sheet is that of an Alabama mill equipped 
with Sutton, Steele and Steele dry tables. Several other Alabama mills 
were similarly equipped, but to the best of the writer's knowledge the 
process did not prove successful. In its chief features, the system here 
outlined is similar to the dry concentrating process installed in a number 



73 

of Canadian mills. In the case of the latter, also, the method has not been 
a success, recovery averaging only 50-60 per cent of the graphite in the 
ore; in addition to which, mica was not wholly eliminated, and the cost of 
production, due largely to frequent shut-downs for repairs and adjustments 
to the numerous belts, pulleys, and elevators, proved excessive. 

The entire mill system here outlined was devised by the Sutton, Steele 
and Steele, Mfg. Mining and Milling Company, Dallas, Texas, and most 
of the equipment was supplied by the same firm. 

The results shown in Fig. 15 were obtained by the above-mentioned 
firm on a 20-ton trial consignment of Alabama ore. The tables used in 
this test appear to have been exclusively of 2-section type; whereas in the 
mill installation shown, 3-section tables were substituted, the middlings being 
returned to the deduster circuit. The heads do not appear to have been 
analysed, so that only the actual recovery and not the percentage of recov- 
ery is shown. Assuming a graphite content of 3 per cent for the heads, 
the results shown give a percentage of recovery of 80 per cent, which is 
unusually high for graphite concentrates made by a dry process. 

AIR CLASSIFIERS. 



The air classifier shown in flow sheets, Figs. 37 and 38, is a device 
peculiar to the Alabama field. It originated in one of the Ashland mills, 
and has since been installed in a number of plants. Fig. 16 shows the chief 
features of the classifier, which is exceedingly simple in design, and can be 



XL ba > 

'_^FAN*-AIR CURRENT* — 



FEED ROLLER 



■R. 




j 

'ON\7 J 




Fig. 16. Section through type of air classifiers used in Alabama mills. Dimensions 

approximate only. 

quickly and cheaply installed. The device is nothing more than a large 
box or chamber, open at the front, and having an ordinary electric exhaust 
fan set into the back. In the front opening is arranged a series of angle- 
iron baffles, above which is set the feed hopper. This is fitted with a feed 
roller, over which the material falls to the baffles. The suction caused by 
the fan at the back draws the lighter graphite into the chamber, while the 
heavier gangue particles fall down through and in front of the baffles. 
The lightest particles are drawn to the back of the chamber, while the 
coarser flake falls immediately behind the baffles. The chamber is usually 

67945—6-1 



74 

provided with three collecting hoppers, for dust, middlings, and coarse 
graphite. 

The device is used at different stages in the various mills, some employ- 
ing it to effect an initial concentration of the crushed ore from the dryer, 
before it passes to the washers, while in other cases it is used to treat the 
concentrate from the washers. While it may possibly be used to advan- 
tage at either stage, it is most useful when employed to treat the crude ore, 
since by means of it a very large proportion of gangue is simply and cheaply 
eliminated at the outset. 

There is a certain amount of loss of graphite incidental to the use of 
this classifier, owing to the fact that a proportion of the gangue particles 
carry attached graphite, but most of this loss would probably occur in any 
case in the washers, and it is doubtful if such attached graphite can be 
profitably recovered. In flow sheet Fig. 37, this heavy sand is passed 
through rolls and returned to the circuit. Results of operation of the classi- 
fier on both crude ore and concentrates are shown below : — 





Graphite 

in 

ore. 


Graphite 

in 
tailings. 


Percentage 

of 

loss. 




Crude ore 


3 • 45 per cent 
2-55 " 


1 • 35 per cent 
1-01 " 


39-1 




39-6 


Concentrates 


62-80 per cent 
48-80 " 


4 • 68 per cent 
1-83 " 


7-4 




3-7 



A device operating on somewhat similar lines to the above was patented 
by J. Labouglie, of Buckingham, Quebec, in 1876, but never found adoption 
in Canadian mills. 

Another and rather more elaborate air classifier that was installed in 
one Canadian mill about 30 years ago was known as the Nappenberger 
separator. In this device, the dry, ground ore was dropped down a deep 
well or shaft, measuring 1 foot X 2 feet, and in its fall encountered air blasts 
directed horizontally across the shaft. These blasts carried the lighter 
graphite through screens set in the opposite wall, while the gangue fell 
through them. The air blasts were arranged in increasing strength from 
top to bottom, so that the finest graphite particles were removed at the 
top, and the coarser flake near the bottom of the shaft. 

What is sometimes called a " barrel machine " has been employed in 
several Canadian mills using the dry concentrating process. It consists of 
a revolving cylinder, slightly inclined, and having narrow flanges extending 
throughout its length. The discharge (lower) end is open, while the feed 
end fits snugly into a stationary chest connected to the suction pipe of an 
exhaust fan. The ore is fed into the upper end of the cylinder, and is 
carried up by the flanges, and dropped through the current of air sucked 
through the cylinder. The tails are discharged from the lower end, while 
the concentrates are blown into a dust collector. As in the case of all such 
pneumatic classifiers, it is essential that the feed be carefully sized. 



ROLLS AND SCREENS. 



In recent years, a number of Canadian* mills have been equipped 
with a dry concentrating system employing a succession of rolls and screens 
to effect a gradual elimination of gangue, the graphite flakes passing 



75 

through the rolls with the production of a relatively small amount of fines, 
while the more brittle calcite, quartz, etc., are reduced to powder. The 
latter is removed by screens interposed between successive sets of rolls, 
while the fine dust is sucked out by means of fans. One of the chief causes 
of the failure of this system of concentration to make a clean product is the 
large amount of mica commonly present in Canadian graphite ores. The 
mica being tough, and of the same general form as the graphite flakes, 
passes through the rolls with the latter and forms the chief impurity in the 
concentrates made by this method. The extraction achieved is also low, 
and while- exact figures are not available, it is estimated from assays of 
the tailings at several mills that the average recovery in the mills using 
rolls is not over 50-60 per cent of the graphite in the ore. While this loss 
may in some cases represent largely graphite fines, the tailings from one 
such mill, which were found to contain 6-14 per cent carbon, gave, on 
treatment by the Callow flotation process, a product containing 45-6 per 
cent of +80-mesh flake assaying 72-6 per cent carbon. 

The style of machine used in the above system is that shown in Plate 
XXXI. This is a six roller mill of the type commonly used in grinding 
provender, and known as the " King Bee " mill (W. and J. G. Greey, 
Toronto). It contains three pairs of rolls, one above the other, each roll 
being belt-driven. The rolls are smooth and of equal diameter, the usual 
size being 9 X 30 inches. The machine requires 25 horse-power for operation. 
Both rolls of each pair are run at the same speed, which is about 500 r. p. m. 
The number of such machines used in series varies in the different mills, 
but is usually four or five, exclusive of the final so-called polishing rolls. 
The latter are machines of precisely similar type, but the rolls are differ- 
ential, the respective speeds being 9:7. This adjustment is made in order 
to exert a certain degree of rubbing action on the flake, which tends to 
loosen any fine gangue that has become pressed into it during its passage 
through the grinding rolls. 

Plate XXXII shows an installation of " King Bee " rolls in a mill in 
the Buckingham district, Que. The rolls of each machine are set a little 
closer than those of the preceding one, so that the product from each under- 
goes a further degree of comminution in the succeeding machine. 

Fig. 17 shows a flow sheet of a mill in the Buckingham district equipped 
with the above system of concentration. The carbon content of the 
products made by this mill during a thirteen months' period is stated to 
have averaged as follows: — 

No. 1, 91-3 per cent 
No. 2, 76-1 per cent 
Dust, 57 • 1 per cent. 

In Fig. 18 is shown a combination system of rolls and dry tables, 
giving the approximate amounts of the various products made at the 
different stages. 

The usual heavy crushing equipment in Canadian mills using the dry 
process consists of one or more gyratory crushers, followed by two sets of 
roughing rolls, respectively 36" X 24" and 30" X 20". The preliminary 
drying of the ore assists materially in rendering it friable, as it decrepitates 
a great part of the calcite present in most ores. G3^ratory crushers give 
better results than jaw crushers, owing to the latter often becoming so 
coated with graphite that pieces of ore simply slide up and down without 
being broken. 



76 



Drying ft/n 
/& Gates crusher 
Trommel / 



Throughs Overs 

I 

2 no 'Gates crusher 



/. s > Heavy no/ /s 36*24' 



Screen 4» 



Through. 



Overs 



2 n ° 'heavy ro//s 
Screen 4?" 



Thnoughs 



Overs 



/ s -*/?o//s 3~*36" 
Dou6/e screen (40 8/00 mesh) 

T^ 1 

-iOO 



-4O+/00 
2" d /?o//s, 3"«36' 



Doob/e screen/ 



'mesh) 



+60 



-60+100 
3 rd #o//s3*36'' 



-ZOO 



Dou6/e screen (30 £00 mesA) 

I 1 1 



+90 



-90+/00 
4* /?o//s. 3*36 

Screen (30 mesh) 



-/GO 



Overs 
-J 



Throughs 



Screen (ZOmesh) 



Overs 

Po//sA/ng ro/& 

Screen /SO mes h] 



Throughs 



Overs 



Pohsh/ng ro//s 
I 

Screen f /SO mes h/ 

Throughs 




Screen y /SO mes hy 
Overs Throughs 

Screen f/00 mesh) Dust proc/uct 
j 

Overs Throughs 

I I 

A/°/ f/ake A* 2 f /ate 



To waste 



Fig. 17. Flow sheet of dry concentration system, employing rolls, as installed in a Quebec 

mill. 



Charge. /SO tdns 

Drying kiln 

A/° S dates crusher 

TrommeJ I 



Overs 
Al°3 Gates crusher 



Heavy rolls 36-24' 
Trommel (10 mesh) 



Overs 

Heavy rolls 30'- 20' 

Trommel (IQmesh ) 

Overs Throughs 



Throughs 



Crushed ore bin 
\IS0T 

Dcduster 

\i44r \er 

Overs Throughs 

Screen (16 mesh) 



\76ST 
Overs 
^7sT~ 



Deduster 
\83ST \-fT 

Overs Throughs 

Screen (30 mesh) 
pir \4Z5T 

Overs Throughs 



\67S T 
Throughs 

Screen {30mf>sh > 
[35f \4IST 

Overs Throughs 

Sut ton. Steele & SteeJe dry table 
\ijf ]ii~T \2T 

Tails Midds 



Deduster 
\365T \45T 

Overs Throughs 



Screen (30 • mesh ' 
(IT \36ST 

Overs Throughs 



\6ST 
Overs 



120-5 T ■ 
Screen (60 mesh) 



Dust chamber 



Screen (/SO mesh ) 
[17 \/25T 

Throughs 



\60T 



D-'j 



Overs 



IsSST 

Throughs 

Screen ISO mesh) 



60mesh 
table 



Bin 60 -90 mesh 



124ST 

Throughs 

Sin SO -ISO mesh 



~l?T \285T 
Cones Tails. 



\2ST \24 T 
Cones Tails 



Dry table 



ysi 

Cones 



r 

Screen (70 mesh! 



Screen (70 mesh) 



Throughs 

Polishing rolls 
Screen \/50mesh) 
Throughs Over. 



Overs 
fbhshmg rolls 

Screen (/SO mesh) 

I \ OST 

Overs Throughs 



Screen (90 mesh) 



WSr 
Tails 



Throughs 

\ 
Dry table 



Screen (/SO mesh) 

I l 3 ^ 

Overs Throughs 

Screen QOmesh ) 

|Jr \/st 

Overs Throughs 



A/°/product A/° 2product 
REFINING 



4T 

Dust product 



CONCENTRATING 



Fig. 18. Flow sheet of dry concentration system by means of a combination of rolls and tables, as installed in a Quebec mill. 
67945— p. 76 



Fig. 17. 



77 







35 
c£ 



78 

The large amount of dust produced in dry mills is very objectionable, 
and there is seldom any attempt made to install an adequate system of 
dust collection. The chief objections to the dry system outlined above 
include failure to make a satisfactory recovery; inability to eliminate mica 
from the concentrates, and the large number of belts, elevators, -etc., 
required, necessitating frequent shut-downs for repairs. 

Details of flow sheet Fig. 19: 

1. Vertical kiln — oval, 5' x 7' x 18', plus stone base 14' high. 

2. Telsmith crusher No. 5 — down to 2\" . Inclined elevator El. 

3. Eureka jaw crusher — down to 1". 

4. 40-ton steel, hopper-bottom bin. Vertical elevator E2. 

5. Automatic roll feeder. Vertical elevator E3. 

6. 36" x 16" ridged rolls — Jenckes Machine Co. — down to \" . Vertical elevator E4. 

7. Screen: hexagonal trommel, No. 8 steel cloth (|"), 30" diam. x 8'. 

8. Rolls 16" x 10" (Krom)— down to \" . Vertical elevator E5. 

9. Rolls 9" x 30" (special) — down to 24 mesh. (Double roll on one frame, 2 sets, feed 

split.) 

10. Screen: hexagonal trommel, No. 8 steel cloth (i"), 30" x 10'. (2 ft. of 1" punched 

plate.) 

11. Rolls 9" x 30" (special) — down to 24 mesh. (Double roll on one frame, 2 sets, feed 

split.) 

12. Rolls 16" x 10" (Krom)— down to \" . Vertical elevator E6. 

13. Screen: hexagonal trommel, No. 8 steel cloth (§"), 30" x 10'. (2 ft. of f " punched 

plate.) Vertical elevator E7. 

14. Barrel machine — to take off fines. Acts as classifier. 

15. Suction fan. 

16. Screen: hexagonal trommel, dressed with 24 mesh steel cloth (special). 

17. Sutton, Steele and Steele dry table No. 1, treating 24-70 mesh feed. Vertical elevator 

(for middlings) E8. 

18. Rolls 9" x 30" (special)— down to 70-100 mesh. Vertical elevator E9. 

19. Barrel machine — to take off fines. 

20. Screen: hexagonal trommel 30" x 10', dressed with 70 mesh gauze. 

21. Sutton, Steele and Steele dry table No. 2 — treating 70-100 mesh feed. Vertical 

elevator (to concentrates bin) E10. 

22. Screen, 30" x 10', dressed with 48 mesh gauze. 

23. Rolls 9" x 30": polishing rolls— single. 

24. Screen: hexagonal trommel, 30" x 10', dressed with No. 10 silk bolting-cloth. Ele- 

vator Ell. 

25. Sutton, Steele and Steele dry table No. 3. Elevator E12 (middlings). Elevator E13 

(concentrates) . 

26. Screen: hexagonal trommel, 30" x 10', dressed with 80 mesh silk cloth. 

27. Burr mill. 

28. Sutton, Steele and Steele dry table No. 4. Elevator E14 (middlings). Elevator E15 

(concentrates) . 

29. Screen: hexagonal trommel, 30" x 10', dressed with No. 7 silk cloth. 

30. Sutton, Steele and Steele dry table No. 5. 

31. Screen: hexagonal trommel, 30" x 10', dressed with No. 15 silk cloth. Elevator E16* 

32. Screen: hexagonal trommel, 30" x 10', dressed with No. 15 silk cloth. 

33. Rolls, 9" x 30" (special): polishing rolls. 

34. Screen, 30" x 10', dressed with No. 15 silk cloth. Elevator E17. 

35. Screen, 30" x 10', dressed with No. 15 silk cloth. 

36. Burr mill. 

37. Screen, 30" x 10', dressed with No. 15 silk cloth. Elevator E18. 

38. Screen, 30" x 10', dressed with No. 7 gauze. Elevator E19. 

39. Suction fan. 

40. Suction fan. 

41. Screen, 30" x 10", dressed with No. 10 silk bolting cloth. 

42. Screen, 30" x 10", dressed with No. 10 silk bolting cloth. 

ELECTROSTATIC MACHINES. 

In this method of concentration, separation of the mineral particles is 
effected by dropping them through an electric field, where the graphite 



79 

flakes behave differently to the gangue particles, owing, in part, to their 
higher electrical conductivity, and are deflected from the course followed 
by the latter. By an arrangement of successive electric fields, the tailings 
from each may be re-treated. 

Two types of electrostatic machines have been employed in the con- 
centration of graphite ores, namely the Sutton, Steele and Steele di-electric 
separator and the Huff electrostatic separator. Both machines operate on 
essentially the same principle, but the two types vary considerably in their 
construction. 

As far as known, the Sutton, Steele and Steele separator (Sutton^ 
Steele and Steele Company, Dallas, Texas) has been installed in only one 
graphite mill, situated in the Buckingham district, Province of Quebec. 
The machine was installed some years ago, and is reported to have given 
satisfactory results. It was used to clean the concentrates produced by 
the Canadian dry process, employing rolls and screens, the No. 1 and 
No. 2 flake being treated separately. It is claimed that the No. 1 flake con- 
centrates from the rolls are raised from 65 per cent carbon content to 92 
per cent by this machine. 

The machine measures about 5 feet in length by 4 feet in width, and 
stands about 6 feet high. The feed falls onto a steam-heated apron, and 
thence to a bin, similarly heated. From the latter, it passes over a shaking 
apron, which spreads the particles evenly and from which they pass over a 
slowly revolving brass roller. In front of this roller is set a parallel, wood- 
covered brass rod, from which extends a single row of 1" needles. These 
needles, with the revolving brass roller, act as the electrodes for creating 
the electric field. They project toward the feed roller, and are spaced 
I inch apart, their points being set at a distance of about 2 inches from 
the roller. Both roller and rod electrode are insulated from the rest of the 
machine, the former being grounded. The latter is connected with a 
generator (in the mill in question, this is a Holtz type electrical machine). 
The amount of current required is small, but the potential is high, being 
about 20,000 volts. On passing into the electric field formed between the 
needle points and the feed roller, the graphite flakes are attracted toward 
the former and fall into the concentrate hopper, while the gangue particles 
tend to follow the roller. Through interference by the particles, and for 
other reasons, all of the graphite present in the feed is not removed in the 
one operation, and the tailings from the first field pass through a second, 
which extracts the remaining free flake. Plate XXXIII shows a view of a 
Sutton, Steele and Steele separator, equipped for three electric fields. 

The Huff electrostatic separator (International Carbon Products 
Company, 120 Broadway, New York) is illustrated in Fig. 20. This type 
of machine was formerly in use in two Ontario graphite mills, and was 
employed, as in the case of the preceding type, to clean concentrates pro- 
duced by the dry process. At the present time, no Canadian graphite 
mill uses the machine, and its use is believed to be confined to one Alabama 
plant and a mill in Texas. The former is reported to produce an extremely 
high grade flake. The separator is stated to have operated with consider- 
able success, also, in the two Canadian mills alluded to above. 

The machine differs from the preceding type in the greater number ot 
electric fields employed, and also in the style of electrodes used, these being 
plain, uncased rods, instead of needle points. Depending on the richness 
of the ore to be treated, the number of electrodes in operation can be varied 
from a maximum of eighteen, down, and many minor adjustments, such as 



80 

the distance between electrode and roller (width of electric field), angle of 
fall, etc., are possible. For a 200-ton installation, a 3 horse-power motor is 
required, delivering the current at from 10,000 to 40,000 volts, depending 
on the nature of the ore. 



Crushed Ore 



Feed roller 



-Electrodes 




laiiings Concentrates 

Middlings 



Fig 20. Section through Huff electrostatic separator. 

In Plate XXXIV is shown diagrammatically the principle of operation 
of an electrostatic separator. For good results, the ore must be bone dry 
and preferably warm, and the air of the chamber in which the machines are 
placed should also be dr}^. On account of limited capacity and the close 
attention that the machines require for successful operation, it is question- 
able whether electrostatic separation can be profitably practised on graphite 
ores. 

Concentration by Wet Methods. 



buddles. 



Buddies were probably the earliest method used for concentrating 
graphite on this continent, and the mill, of the Lochaber Plumbago Mining 
Company, the first recorded graphite operators in Canada, was equipped 
with buddies. While many and varied methods of concentration have 



81 

been practised and discarded since those early days, it is noteworthy that 
two of the largest graphite mines on the American continent (the American 
Graphite Company, in New York, and the Black Donald Graphite Com- 
pany, in Ontario) retained the buddle system until 1918. The latter 
Company still continue their use 1 , but the former discarded them during 
1918 in favour of the Callow oil flotation process. 

Buddies effect a satisfactory recovery from practically all types of 
graphite ore, and they have the merit of being simple to operate and of 
requiring little attention. Their capacity is rather limited, however, and 
they take up an excessive amount of floor space, besides which the products 



Jaw crusher {Meads 7$5per cent carbon) 

Stamps {Screen 8 mes/)J 
//ydraui/c c/assrf/er 

J A 

Fine Coarse 

Sett/ mg tank 



F/nes 



r 



Richards pu/sator c/as s/rfer 



bc/dd/e 



Concentrates M/dd/ings Tailings 

>— 4 — 



Hfasn/nji ree/s 
F/ake Sand 



Concentrates 
budd/e 



Coarse 



Sand 



Tesi 



Vtfl/, 



Concentrates M/od/ings Taii/ngs 

I | (36 percent carbonJ 



Ja mes t ab/e 

I — — T^ 1 

Concentrates M/dd//ngs Taih'ngs 
(7% per cent carton) I 



Wasfang reei 



76 3 per cent carwv i (9 35 per cent carbon J 



<Are 

f 



Cutler dryer 
Screen 730 mesh) 



+80 
Hooperjig 
Buhrstone 
Screen 



-80 
Hooper jig 
Suhrstone 
Screen 



To wasbe 



IW 



N*2 Dust iV°/ N?2 Dust 



Fig. 21. Flow sheet showing mill system using buddies, as installed in a New York mill. 

made must be removed by hand, necessitating duplicate equipment, one 
buddle filling while the other is being emptied. When treating low grade 
ores, this entails the handling of large quantities of tailings. 

In Figs. 21 and 22 are shown flow sheets of two mills effecting con- 
centration of graphite by means of buddies. In the case of the former, 
the ore treated is a hard graphitic gneiss carrying 5 per cent of graphite, 
and concentrates are made containing 65 per cent, the recovery being 
about 50 per cent of the graphite in the ore. 

The mill, Fig. 22, treats an exceptionally rich ore (65 per cent of 
graphite), carrying calcite and chlorite as the chief impurities, and while 

1 See note p. 38. // 1 rf I & 



82 
Jatv crus/rer 
/O- Stamp battery 
Budc//e 



7a///ngs 



Overf/ow S/jmes 

L_ 



/v/ter press 

I 
Steam dryer 

I 

A/? /O product 



Tromme/ 



T/troughs Overs 

— "■ Cut/er dryer 



7romme/ 

tM 3 

Tnroug/ts Overs 



/V? /? proc/uct 



Nooper dryj/g 
/hrougns Overs 

I I 

N 9 4 product Buhrstone 

Tromme/ 



Througffs Overs 

Bufirstone N 9 / product 

Tromme/ 



T/trougfis Overs 

-A I 

/rcmme/ /V? 2 product 

Throughs Overs 

I I 

A/?3x product A/°33product 

Fig. 22. Flow sheet of combined wet and dry concentrating system, as installed in an 

Ontario mill. 



83 

no exact figures are available, the buddies probably make concentrates 
approximating 80 per cent. 

The buddies used in graphite mills are of the circular type, and are 
about 16 feet in diameter. In more recent years, their use has been largely 
confined to the New York graphite field. 

MECHANICAL WASHERS. 

Log, Washers. 

This method of concentration has found its greatest adoption in 
Pennsylvania mills. Most of the mills in this State treat a highly 
decomposed, surface ore, the graphite content of which is between 4 and 5 
per cent. The gangue consists principally of quartz and kaolinized feldspar 
with a little mica. In some cases, the ore as it comes to the mill is in the 
form of gravel; in others it is somewhat harder, but is still soft enough 
to be crushed readily in a muller pan. 



7romme/. fe "mesh/ 



Throughs 



Overs 



Log-washers 



Tai/s. 

fto\/s 

Log - washers 



Cones. 



7a//s. 



Log - washers 



Cones. 



Tai/s. 



To waste 



7a//s. 
Log -washers 

Cones. 



Cones 

I 



Gyratory crusher 
/fo//s 



R otary screen, (3 6 meshj 

Overs Throaghs 

IVash/ng *ree/s. (60 meshj 

Rotary dryer (/nd/reet heat) 
Buhrstones 

I 

Screens 

I 



/V°L 



M?2 



Dost 



Dryer 



Spec/a/ -f/ake 

Fig. 23. Flow sheet of mill employing log-washer concentration, Byers, Pennsylvania. 
The ore is very decomposed, and comes to the mill in the form of gravel. 

Log washers are stated to be used, also, in two Alabama mills. 

The log washers used are of two types., continuous-screw and blade. 
The latter are stated to give rather better results than the screw type, 
owing to there being less attrition of the large flake. Fig. 23 shows a 
flow sheet of a Pennsylvania mill equipped with log washers. At this mill, 
of the graphite recovered in the log washer concentrates, about 35 per cent 



84 

remains on a 36-mesh screen. The consumption of water is 120,000 
gallons per 24 hours. 

Rake Washers. 

In some Pennsylvania mills, washers of the rake type have supplanted 
log washers, and are reported to give more satisfactory results. This type 
of washer is a home made appliance and works on the principle of the 
Dorr classifier. It consists of a table 18 feet long and 4 feet wide, set on 
an incline of about 1 in 25. On the two sides are boards 12 inches high 
for holding in the ore. Strips are set along these boards to serve as runways 
on which the rake frame travels on its forward and return stroke. The 
frame is provided with cross pieces at 18-inch intervals, to which are 
attached the rake teeth. These are of iron, 1 inch wide, and are set 



Mutter pan M "grate 
Ra/ce washer 



Taits. 
Rake washer 



Cones 
r?ee/.fS6 mesAj 



7a/ts. 



Cones. Throughs 

Rot/s Reet(36mesh) *— 

Ratce washer Overs Throughs 



Overs 
I 



Cones. 
fteet/36 mesh 



Ta/ts. 



Overs 



,7b waste 



r 

Throughs 



u 



tVash/ng reet. (60 m esh) 
Overs Throughs 



Rake washer 



Cones. 



Taits. 



r?otary dryer 

Fig. 24. Flow sheet of wet concentration system, using rake washers, in a Pennsylvania 

mill. This mill has a capacity of 100 tons of ore per 24 hours, requires 60 H.P. 

for operation, and three men to a shift. 

\\ inches apart. The rows are staggered, and the teeth extend to within 
1 inch of the surface of the table. The frame is actuated by a crank at the 
upper end, and has a play of 18 inches. The rate of travel is twelve 
up-and-down movements in one minute. The ore is fed to the table 
from a central spout set about 3 feet from the lower end. A pipe crosses 
the table 2 feet below the upper end, and from it sprays of water impinge 
on the surface of the ore. Four adjustments are possible, namely pitch 
of table, rate of rake travel, amount and velocity of feed water, and rate 
of feed of ore. In operation, the rake frame travels up the slope with the 
teeth in the ore; at the end of its stroke, the frame is raised and travels 
back with the teeth elevated above the bed. In this way, the coarse sand 
is raked to the upper end of the table, where it discharges, while the water 



85 

washing down the table carries the finer material, including the light 
graphite, to a collecting launder at the lower end. A bed of ore about 

1 inch thick remains undisturbed between the ends of the rakes and the 
table surface, and the total thickness of the ore on the table is about 

2 inches. 

It is claimed that by adding coal oil or kerosene to the feed water, 
a material improvement is effected in the amount of graphite recovered 
in this type of washer. 

According to Dub 1 , the following results have been obtained by the 
use of these washers, kerosene oil being added to the feed : — 



Heads. 


Concentrates. 


Tailings. 


4 • 52 per cent carbon 
3-56 " 


62 • 00 per cent carbon 
72-07 


2 • 19 per cent carbon 
1-79 " 



WET TABLES. 

Wet tables have not been adopted to any large extent in graphite 
concentration. One Canadian mill, however, is at the present time 
equipped with Krupp-Ferraris tables, and the James table has been 
employed in New York and Pennsylvania mills. It is a common practice 
to lightly oil the feed for wet tables, this resulting in a marked improvement 
in extraction. The plants using James tables report satisfactory results, 
especially with the addition of oil to the feed. The Canadian mill using 




Fig. 25. Ferraris type of wet table. 

Krupp-Ferraris tables has been in operation for the past five years, and 
makes concentrates running 60 per cent carbon, or better, from a 10-12 
per cent ore. 

An installation of Ferraris wet tables is shown in Plate XXXV, and 
the James table is illustrated in Fig. 26. The power required for operation 
of both types is 0-5 to 1 H.P., and the water consumption 5 to 9 gallons 
per minute. Their capacity is about 1,000 pounds per hour. 

Dub, G. D., Preparation of Crucible Graphite, U. S. Bureau of Mines, Dec. 1918, p. 15. 



86 




Fig. 26. James type of wet table. 
FLOTATION. 

Considerable attention has been devoted in the last few years to the 
possibilities of notation as a method of concentrating graphite ores. 

Flotation, as applicable to graphite concentration, may be of two 
kinds, each embodying quite different features and based upon different 
systems of manipulation. These two methods are, respectively, frothing 
oil notation, and film or surface tension flotation. 

Frothing Oil Flotation. 

This method utilizes the property possessed by fine particles of certain 
minerals — notably sulphides, as well as by graphite, when made into a 
pulp with water to which a certain small proportion of frothing oil or oils 
has been added, and upon the subsequent formation within the pulp 
of a mass of bubbles (froth) either by mechanical agitation or by the 
injection of air — of being carried to the surface, while the gangue, (silica, 
calcite, mica, feldspar, etc.) sink. The reason for this selective action 
on the part of the various mineral particles is not definitely known, and has 
been ascribed to many causes, including a superior affinity by metallic 
surfaces for air, which preference is enhanced by the presence on them 
of oil or grease. In this way, the metallic (and graphite) particles become 
attached to the bubbles formed in the pulp and are carried by them to the 
surface, where they may be skimmed off, or, as takes place in actual 
practice, are automatically carried forward by surface flow over the lip 
or edge of the tank or cell in which the operation is carried out. 1 

All systems of concentration of ores by the frothing oil flotation 
method are alike in their basic principles. These are, briefly, the mixing 

1 For a consideration of the underlying principles of frothing flotation, see The Flotation Pro- 
cess, by T. A. Rickard, published by the Mining and Scientific Press, San Francisco; also, The 
Flotation Process, by H. A. Megraw, 2nd edition, 1918. McGraw-Hill Publishing Company, New- 
York. 



87 



Jew crusher 



Bin 

Ball mi// 
Tube mi// 




ifa 



k 

Oversize 

Sana tab/e 



Trommel (40 mesh) 



Undersize 



Tails Afidds. Cones 

Washing Screen 

\ " IT 



Gangue s/imes 




Cones. 
I 



"1 

Oversize 

Sand tab/e 

\ * } 

Cones Midds. Tails. 



Tromme/ (60 mesh). 



Vnder 



Cones. 

-I Washing Screen 

\ \ 

ie s/imes Cones. 
I 



Tails 



Hydraulic classifier 
3 Spigots Overflow 



Sand' tables 

Cones. 



Washing Screen s 
Gangue slimes Cones. 



Hydraulic b/assifier 

r — — } 

4- Spigots Overflow 

Slime ' tables 



Cones 
W ashing Scree ns 
Gangue slimes Cones. 



Sand pump f 



Washing Screen 
Cones. Gangue slimes 



.one 




Oversize 
Sand table 



Cones. Midds. Tans. 

I I L 

Washing Screen I . > 

Cones Gangue s/imes 



Hydraulic classrfier 
Overflow 



Sand tables 



Codes. Midds, 



Washing Sc 



Tails. 
I — i 



Cones. Gangue slimes 



Hydraulic classifier 
Outflow 



Slime tables 
I ~f 



Cones. Midds. 
Wa shing Scree ns 
COncs. Gangue slimes 



1 
Tails 



Slime 



tables 



\ f } 

Cones Midds. Tails. 

I, 



Washing Screen s 
Cones. Gangue' s/imes 



Washing Screen 

Gangue slimes Cones 

Vacuum* filter 



Clear water 



Cones 

Dryer 
Polishing rpl/s 
Screed (30 meshl 

Overs Throughs 

A/°/Product Screen {/SO mesh) 

Overs Throughs 

Dry tab/e Dust Product 

{ °y } 

Cones Midds Tails 
A°2 Product I I 



Tai/s. 
to waste 



To waste 



Tads' 
to waste 



Fig. 27. Flow sheet of wet concentration system, using Ferraris tables, as installedjn 

Quebec mill. 
67945—7 



88 

of the finely ground ore with water to form what is known as the pulp, 
the emulsifying of the pulp by the addition of a suitable frothing oil, and 
finally the production within the pulp of a mass of air bubbles (froth), 
which floats the valuable mineral to the surface. The production of the 
froth is dependent upon the presence of air in the pulp, and various methods 
of introducing this air have been devised. Thus, by the Minerals Separa- 
tion system the air is beaten into the pulp by means of paddles or stirrers; 
by the Callow system, it is injected through a canvas or other suitable 
porous bottom; by the Simplex system, it is introduced by means of jets 
of water impinging on the surface of the liquid in the cell. 

All of the above-mentioned systems of oil flotation have been installed 
in Alabama graphite mills, and, it is claimed, have given satisfactory 
results. According to Dub, 1 eight of the mills employ the Callow system, 
four, the Simplex, and four, Minerals Separation cells; in addition to 
which, six plants have installed, or intended to install, cells combining some 
of the principles of these systems. 

* In Pennsylvania, one mill is equipped with the Minerals Separation 
system. 

In New York, the mill of the American Graphite Company has lately 
been equipped with the Callow system, and excellent results are claimed to 
have been secured. 

In Canada, the Callow system was installed in 1918 in one mill in the 
Buckingham district, but unfortunately the mill burned down before any 
definite results were achieved. At the present time, (March 1919) one 
other mill in the same district has almost completed the installation of 
Callow ce\l\ and the same system is under consideration by a third plant. 

Frothi g oil flotation for concentrating graphite has only been employed 
in actual pi.ictice for the last two or three years, and for the greater part 
of this period the process may be said to have been merely in its experi- 
mental stages. It- is, therefore, perhaps, a little early to generalize on 
what the method can achieve, since, for best results, considerable knowledge 
of the principles of flotation is necessary, and the adjustments that are 
required to be made in the mills of different districts owing to variations in 
the character of the ore to be treated, size of flake, etc., are many and varied. 
Results obtained in the Alabama mills, however, and also in the one mill in 
New York, using oil flotation, have demonstrated that the process can 
cheaply and effectively treat the ore of both districts. Considerable 
experimental work has been carried out, also, on Canadian ores with the 
Callow system, the results being very satisfactory. Frothing oil flotation 
would appear to offer the cheapest and most efficient means of concentrating 
graphite that has yet been devised. 

One of the chief difficulties connected with the process is in combining 
good recovery with a high grade of concentrates. If a froth be produced 
sufficiently strong to float all of the flake, both large and small, a consider- 
able proportion of fine and attached gangue is also floated, and a dirty 
concentrate results; while if the froth be adjusted to make a clean con- 
centrate, much of the larger flake passes into the tailings. The difficulty 
may be at least partially overcome by close attention to sizing of the feed, 
and the treatment of the different sizes by individual cells. 2 

1 Op. cit., p. 9. 

2 Data relating to the various factors that may affect the efficient operation of flotation plants 
are contained in Flotation for the Practical Mill Man, by F. G. Moses, Chem. and Metall. Engi- 
neering, June 1, 1919, pp. 571-7. 



89 

While the figures quoted of experimental work on Canadian ores with 
the Callow system would tend to indicate that the graphite delivered 
from the cleaner cell is sufficiently pure to be marketed as No. 1 flake 
without any further cleaning, such good results are probably not obtainable 
in actual mill practice, the flotation concentrates requiring finishing over 
burrstones or polishing rolls. 

Ball or pebble mills are almost invariably used for grinding the feed 
for oil flotation cells, and most of the leading types of such mills are repre- 
sented in the various plants. While comparative data on the destructive 
effect of different grinding machines on graphite flake is lacking, wet grind- 
ing in a ball mill of ore to be concentrated by wet means seems to be gaining 
increased favour. For use with oil flotation installations, and treating a 
hard ore, ball mills are perhaps to be preferred, as, by adding the frothing 
oil to the charge, the ore is ground and the pulp emulsified at one operation. 
Where rolls or other grinding machines are employed, emulsifying of the 
pulp may be effected satisfactorily by the action of elevators and in the 
hydraulic classifier. 

While differing in certain details of construction and operation, all 
systems of frothing oil flotation employ a series of tanks, or cells, in which 
frothing of the pulp takes place. The first cell effects an initial concentra- 
tion, and the concentrates from it pass to a second, and so on, through as 
many cells as may be found necessary to raise the grade to the point 
desired. By interposing additional ball mills or other grinding machines 
between successive cells or groups of cells, the concentrate made by the 
last cell can be raised to a high degree of purity. 

It has been conjectured that graphite refined by the oil flotation 
method may possibly become so contaminated by the flotation oils used as 
to be unsuitable for crucible work. The amount of such oils used, however, 
is relatively very small, and since the finished product is subjected to a 
considerable degree of heat in the final drying, any oil that may adhere to 
the flake is driven off during this operation. 

A system of concentration that may be described as a combination of 
the oil flotation method with log washing was devised by J. F. Latimer, of 
Toronto, Ontario, in 1908. The apparatus employed 1 consists of a round 
washer or cell, tapering to a point at the bottom, where the tailings discharge 
spigot is situated. A screen is placed within the washer at the point 
where it starts to taper. A hollow, vertical shaft passes down through the 
centre of the washer and screen, terminating just below the latter. Adjust- 
able paddles are fixed to the shaft just above the screen, and the shaft is 
rotated by a pulley. In operation, the pulverized ore is first mixed with a 
small amount of crude oil. Water is led into the washer through the 
hollow shaft, and as soon as it starts to flow up through the screen, the ore 
is fed in near the centre of the washer. The gangue particles pass down 
through the screen, while the graphite floats out through a spout near the 
top of the washer. If necessary, a series of such washers may be employed, 
each one taking the concentrates from the preceding one. The concen- 
trates from the last washer pass into an inclined trough, or log washer, 
which discharges clean graphite at the upper 2 end. 

The Kendall separator (U. S. Patent, No. 771,075) is operated along 
very similar lines to the above. A mill in the Buckingham district, Quebec, 

1 See Can. Min. Journ., Vol. 29, 1908, p. 142. U. S. Patents 851,599 and 851,600, April 23, 1907. 

2 This would be the reverse of what takes place in actual log washer concentration, the gangue 
discharging at the upper end and the graphite at the lower end. 

67945—71 



90 

was equipped about ten years ago with this type of separator, but the 
results did not prove satisfactory and the process was abandoned. 

The following list of United States patents relating to the concentrating 
of graphite by oil notation, or by methods akin to oil notation, is taken 
from Bulletin No. 8 of the Utah Engineering Experiment Station, June 
1916, by R. S. Lewis and O. C. Ralston. The abstracts of each patent, 
given in the above Bulletin, are not quoted, but copies of the patents may 
be obtained at a cost of 5 cents each from the Commissioner of Patents, 
Washington, D.C.: 

486,485. Nov. 22, 1892. Nibelius. 

678,860. July 23, 1901. Brumell. 

679,473. July 30, 1901. Davis. 

688,279. Dec. 10, 1901. Allen. 

734,641. July 28, 1903. Wheelock. 

736,381. Aug. 18, 1903. Glogner. 

745,960. Dec. 1, 1903. Good. 

763,859. June 28, 1904. Darling. 

771,075. Sept. 27, 1904. Kendall. 

795,823. Aug. 1, 1905. Darling. 

816,303. Mar. 27, 1906. Davis. 



Callow System. 

The Callow system of oil notation has probably been more extensively 
adopted in graphite mills than any other, and while still in process of 
development for the treatment of graphite ores, has successfully demon- 
strated its ability to concentrate graphite both cheaply and efficiently. 
In this system, frothing is effected by forcing air into the pulp through a 
porous medium, such as canvas, forming the bottom of the cell. 

Figs. 28 and 29 show Callow installations at two mills in the United 
States. Fig. 28 is the flow sheet of a mill in Alabama, while Fig. 29 shows 
the installation at a mill in New York. In the case of Fig. 28, the ore is 
soft, and carries about 3 per cent of graphite, while that treated by flow 
sheet Fig. 29 is hard and runs about 6 per cent. The latter type of installa- 
tion, with minor modifications, is suggested as the more suitable for treating 
Canadian gneissic ores. In the case of the softer, graphitic limestones, 
the second ball mill might possibly be dispensed with. The original 
Callow installation at the New York mill contained only the Hardinge 
mill A, and with this equipment a one-product concentrate was secured 
running 70-75 per cent carbon, with a 95 per cent extraction. With the 
additional mill B, it is hoped to raise the grade of product to 90 per cent 
or better. The concentrates from this mill undergo a further refining by 
means of burrstones and screens. 

On the following pages are shown the results of tests made on a series 
of samples of Canadian graphite ores with the Callow system. 



91 




92 



^ 




51} 




<t 




d 


1 



^__y 



93 

Ore: Disseminated flake graphite — chief impurities, calcite, mica, 
quartz, pyrites. Heads, by products, 12-81 per cent carbon. Ground to 
40 mesh and oiled at the rate of 11 pounds per ton. Oils used: General 
Engineering Company's No. 136, 90 per cent; No. 56, 10 per cent. 

Test made by General Engineering Company's laboratory, Ottawa. 



Treatment. 


Sample 

No. 


Description. 


Weight, 
per cent. 


Assay, 
per cent 
carbon. 


Carbon 

content 
= assay X 

per cent 
of weight. 


Percentage 

of 
recovery 
or loss, 
carbon. 


Sample No. 1 
floated in Cal- 


2 
3 
1 


First flotation concen- 


24-8 

75-2 


50-28 
0-46 

12-81 


1,246-86 
34-60 


97-3 


low pneumatic 
machine. 


First flotation tailings. . 


2-7 


Heads, by products 


100-0 


1,281-46 


100-0 


Sample No. 2 
(flotation con- 


4 
5 

2 


Second flotation concen- 


14-2 
10-6 


85-2 

3-5 

50-3 


1,209-76 
37-10 


94-41 


centrates) re- 
floated in Cal- 


Second flotation midd- 


2-89 


low pneumatic 
machine 






Feed, by products. 


24-8 


1,246-86 


97-30 


Sample No. 4 
(second flota- 


6 

7 

4 


+ 80 mesh 


9-0 
5-2 


91-5 
74-3 

85-2 


823-50 
386-26 


64-27 




- 80 " 


30-14 


trates) sized as 
indicated 






Feed, by products 


14-2 


1,209-76 


94-41 



SUMMARY. 

Yield per ton of ore. 



Pounds. 


Product. 


Carbon, 
per cent 


Per cent 

of 

concentrates. 


Percentage of 

total carbon 

in ore. 


180 


+ 80 mesh 


91-50 

74-28 

3-50 

0-46 


63-4 
36-6 


64-27 


104 


— 80 mesh 


30-14 


212 


Re-treatment product 


2-89 


1,504 


Tailings 




2-70 










2,000 


100-0 


100-00 



94 

Ore: Plumbago or crystalline graphite, mixed with some flake. Chief 
impurities, calcite, quartz, feldspar and pyroxene. Heads, by products, 
45-51 per cent carbon. Ground to 30 mesh, and oiled at the rate of 14 
pounds per ton. Oils used: General Engineering Company's No. 136, 
70 per cent; No. 6, 15 per cent and No. C-41, 15 per cent. 

Test made by General Engineering Company's laboratory, Ottawa. 



Treatment. 


Sample 
No. 


Description. 


Weight, 
per cent. 


Assay, 
per cent 
carbon. 


Carbon 
content 

= assay X 
per cent 

of weight. 


Percentage 

of 

recovery 

or loss, 

carbon. 


Sample No. 1 


2 
3 
1 


First flotation concen- 


54-6 
45-4 


82-40 
116 

45-51 


4,498-6 
52-7 


98-9 


low pneumatic 
machine 


First flotation tailings . . 


1-1 


Heads, by products 


100-0 


4,551-3 


100-0 


Sample No. 2 
(flotation con- 
centrates) re- 
floated in Cal- 


4 
5 

2 


Second flotation concen- 


49-9 
4-7 


89-40 

7-88 
82-4 


4,461-6 
37-0 


98-1 


Second flotation midd- 
lings 


0-8 


low pneumatic 
machine 






Feed, by products 


54-6 


4,498-6 


98-9 


Sample No. 4 


6 

7 
8 

4 


+ 80 mesh 


30-3 
11-8 

7-8 


95-35 

85-42 
72-38 

89-40 


2,889-1 

1,007-9 

564-6 


63-5 


tion concen- 


+ 150 " 


22-0 


trates) sized as 
indicated 


- 150 " 


12-6 






Feed, by products. . .... 


49-9 


4,461-6 


98-1 



SUMMARY. 
Yield per ton of ore. 



Pounds. 


Product. 


Carbon, 
per cent. 


Per cent 

of 

concentrates. 


Percentage of 

total carbon 

in ore. 


606 


+ 80 mesh 


95-35 

85-42 

72-38 

7-88 

1-16 


60-7 
23-7 
15-6 


63-5 


236 


+150 " 


22-0 


156 


- 150 " 


12-6 


94 


Re-treatment product 


0-8 


908 


Tailings 




1-1 










2,000 


100-00 


100-00 



The following test was made on a representative sample of a tailings 
dump at a mill in the Buckingham district. This mill employed a dry 
system of concentration, which succeeded in extracting only about 50 
per cent of the graphite in the ore. The graphite was all flake, and the 
chief impurities were calcite, mica, feldspar, and pyroxene. The sample 
showed, by products, 6 • 14 per cent carbon. The sample was ground to 
40 mesh, and was oiled at the rate of 2-8 pounds per ton. Oils used: 
General Engineering Company's No. 136, 60 per cent; No. 8, 20 per cent; 
No. 6, 20 per cent. 



95 
Test made by General Engineering Company's laboratory, Ottawa. 



Treatment. 


Sample 

No. 


Description. 


Weight, 
per cent. 


Assay, 
per cent 
carbon. 


Carbon 
content 

= assay X 
per cent 

of weight. 


Percentage 

of 

recovery 

or loss, 

carbon. 


Sample No. 1, 
floated in Cal- 


2 
3 
1 


First flotation concen- 
trates 


12-30 
87-70 


45-10 
0-68 

6-14 


554-82 
59-63 


90-30 


low pneumatic 
machine 


First flotation tailings . . 


9-70 


Heads, by products 


100-00 


614-45 


100-00 


Sample No. 2, 
(flotation con- 
centrates) re- 
floated in Cal- 


4 
5 

2 


Second flotation concen- 
trates 

Second flotation midd- 
lings 


9-35 
2-95 


58-32 

3-24 

45- 10 


545-26 
9-56 


88-73 
1-57 


low pneumatic 
machine 






Feed, by products 


12-30 


554-82 


90-30 


Sample No. 4, 
(second flota- 


6 

7 

4 


+ 80 mesh 


4-27 
5-08 


72-66 
46-26 

58-32 


310-26 
235-00 


50-49 


tion concen- 


- 80 " 


38-24 


trates) screen- 
ed as indicated 






Feed, by products 


9-35 


545-26 


88-73 



SUMMARY. 

Yield per ton of tailings treated. 



Pounds. 


Product. 


Carbon, 
per cent. 


Per cent 

of 

concentrates. 


Percentage of 

total carbon 

in heads. 


85 


+ 80 mesh 


72-66 

46-26 

3-24 

0-68 


45-5 
54-5 


50-49 


102 


- 80 " 


38-24 


59 


Re-treatment product 


1-57 


1,754 


Tailings 




9-70 








2,000 


100-00 


100-00 



Below are given the average results out of a series of five tests made on 
a sample of graphite ore from Lachute, Que., with the Callow pneumatic 
testing machine at the ore testing laboratory of the Mines Branch, Depart- 
ment of Mines. The ore consisted of flake graphite in a gangue of calcite, 
quartz and mica, with a small amount of pyrites, and the sample was 
typical of the, graphite schists of the Quebec area. The carbon content 
was 15 per cent. It was found necessary to crush to a fineness of 30 mesh 
in order to free the flake. In three out of the five runs, the samples were 
crushed to 30 mesh, and in the remainder to 40 mesh. In the case of the 
former, pine oil and coal oil were used, and with the latter No. 25 F.P.L. 
creosote oil. The amount of oil used was between one and two pounds 
per ton of ore. In all cases, the crushed ore was ground for 5 minutes in a 
pebble jar, floated, and the concentrates re-ground in a pebble jar and 
re-floated. 



96 



The results of the tests show that 96-5 per cent of the total graphite 
in the ore is recovered in the concentrates. 



Pounds. 



Product. 



Carbon, 
per cent. 



Percentage of 

total carbon 

in ore. 



73 

101 

311 

401 

1,114 



2,000 



+ 80 mesh 

- 80 + 115 mesh 

— 115 mesh 

Middlings 

Tailings 



92-1 

78-3 

55-8 

1-9 

0-2 



23-4 
23-1 
500 

2-7 



100-0 



A further test was made in the Mines Branch laboratory with the 
Callow pneumatic machine on concentrates from one of the Quebec mills. 
This mill employs a wet system of concentration by means of Ferraris 
tables. The concentrates submitted for test ran carbon 60-10 per cent, 
silica 20-10 per cent, iron 2-20 per cent. The silica was present both as 
attached particles and as a skeleton of either quartz or mica within the 
body of the flakes. The iron was chiefly pyrites and pyrrhotite in the 
form of microscopic particles within the flakes. 

The material was floated, and the grade raised to 72-3 per cent carbon. 
These concentrates were then ground in a pebble mill and re-floated, and 
the final concentrates were found to assay 83-45 per cent carbon. On 
screening, the following results were obtained : — 



Mesh. 


Carbon content. 


Per cent 

of 

concentrates. 


+ 100 


86-50 
82-05 
68-45 
48-32 


78-2 


- 100 + 150 


13-3 


- 150 -f 200 


3-8 


- 200 


4-7 










100-0 



The presence of microscopic quartz, mica, and pyrrhotite within the 
graphite flakes was determined by carefully picking out the largest clean 
flakes from the flotation concentrates and analysing them. It was found 
that these apparently clean flakes assayed as follows: — 

Carbon 92-25 per cent 

Silica 3-00 

Iron and alumina 3-60 " 

Undetermined . 1-15 " 



100-00 



Under the microscope, also, the presence of quartz, pyrrhotite, and 
pyrite, intimately intergrown with the graphite is clearly visible. 

The presence of these microscopic impurities explains why it is impos- 
sible by mechanical methods of concentration to raise the carbon content 
of some flake graphites beyond a certain point. It also shows that con- 



97 

centrates running higher in carbon may more often be secured from 
weathered surface ore than from unweathered, since most of the iron 
sulphide is commonly leached out of the former. The resulting acid also 
attacks any calcite present, thus bringing about a still higher graphite 
content in such ores. For reliable results, therefore, all tests should be 
carried out on fresh, unweathered ore and not on surface samples. 

The following cost data for a Callow installation designed to treat 100 
tons of ore per day have been kindly supplied by the General Engineering 
Company. The plant in question is designed for Alabama ore, and the 
estimated mining costs are, accordingly, considerably lower than the actual 
figures for work in hard rock, as in New York and Canada. On the other 
hand, the average graphite content of the ore in the latter fields is from 
two to five times as high as that of Alabama ore, so that the two things 
may thus be considered as offsetting one another to a large extent. It 
should be stated, also, that the estimated cost of $0.75 per ton for mining 
Alabama ore appears high as compared with the figure quoted to the writer 
by operators, which was $0.25 to $0.35 per ton delivered to the crusher. 

Mill operating costs for plant treating 100 tons graphite per 24 hours in the 

Alabama graphite districts. 

Callow Oil Flotation System. 

1918. 
Labour — 

1 Crusher man $ 4 . 00 

3 Ball mill or roll men at $4 12.00 

3 Flotation men at $4 . 12.00 

3 Labourers at $3 9.00 

1 Mechanic 7.50 

1 Superintendent at $300 per month 10.00 



$54.50 or 54 \ cents 
per ton of ore. 
Power — 

Crusher 20 

Ball mill or rolls . .. 50 

Blower 25 

Re-grinding mill ....... 15 

Miscellaneous 15 



125 
Friction 25 

Total 150 or li H.P. per ton of ore. 150 H.P. 

at $75 per H.P. year, or $0.25 per H.P. day = $37.50 per day or 37£c. 
per ton of ore. 

Flotation Oils — 

200 lbs. coal oil at 7 lbs. per gal. or 30 gals, at 10c. 

per gal $ 3.00 

100 lbs. G.N.S. No. 5 at 7J lbs. per gal. or 14 

gals, at 50c. per gal 7 . 00 



$10.00 or lOc.per ton 



98 

Steel Balls and Liners — 

300 lbs. at 10c. per lb. or $30 per day or 30c. per ton. 

Oil j Waste and Incidental Repairs — 

Estimated at $15 per day or 15c. per ton. 

Summary. 

Labour $ 54 . 50 per day or . 54|c. per ton. 

Power 37.50 

Flotation oils 10.00 " .10 

Balls and liners 30.00 " .30 

Oil, waste and incidentals 15 . 00 " .15 



2 



$147.00 $1.47 

say 1.50 " 

Recapitulation. 

Mining (open cut, soft ore), estimated $0.75 per ton 

Milling 1.50 " 



$2.25 
On 3% ore approximately 2J% would be recovered 
or 50 lbs. per ton, at a cost of 4-5 cents per lb. of all grades. 

Minerals Separation System. 

In this system of frothing oil flotation, frothing of the pulp is effected 
by air entrained or beaten into it by paddles attached to a vertical shaft 
rotating in the frothing tank. 

The system is reported to have been installed in four Alabama mills, 
and is used also in one small plant in Pennsylvania. 

Fig. 30 shows the flow sheet of a mill in Alabama equipped with the 
system. 

According to information furnished by the management, the ore 
treated in this mill contains 2 • 75 per cent of graphite, 2 • 25 per cent being 
regarded as recoverable. The flotation concentrates average 80 per cent 
carbon, and a recovery of 85 per cent (of 2-25) has been achieved. 

It has been found difficult, however, to combine high recovery with a 
clean concentrate, and at the same time preserve the large flake, owing to 
the latter carrying up attached gangue. The denser froth also floats more 
slime gangue. In order to secure a high carbon content for the No. 1 
flake, therefore, it has been found necessary to lower the percentage of 
recovery. With a 65 per cent extraction, it has been found possible to 
make a finished product carrying 85 to 90 per cent carbon. Of the total 
graphite recovered, 45 per cent is in the form of No. 1 flake and 55 per cent 
No. 2 and dust. The ore costs 25 cents delivered to crusher, and the cost 
of production per pound of No. 1 flake is 5 cents. 

At a small mine near Chester Springs, Pennsylvania, soft, powdery 
ore running about 7 per cent graphite is broken up in a No. 2 Jeffrey 
" Lime Pulver " crusher and fed in small batches to a single Minerals 
Separation cell. The concentrates are washed in an 80 mesh reel, drained 
and dried on a hot plate. While only an experimental plant, the concen- 
trates produced by the single rougher cell are reported to assay 80 to 85 
per cent of graphite. The results secured would indicate that, with proper 



99 

equipment, this type of ore is well adapted to concentration by frothing 
oil flotation. 

Jaw crusher 



Tromme/, fi^'mesh) 



Throughs 



Overs 
Crusher 



Dorr Sranc/arc/ 



Pup /ex c/assif/er (o // ac/c/ec/J 
Sane/ S///7?es 



3a//mi// 
I 



/O Rougher ce//s 



Concentrates 
/O C/eaner ce//s 



7a///ngs 

7b waste 



Tai/ings 



Concentrates 
Dorr tn/ckener 



Overflow 



S/imes 
O/iver /v/ter 

Dryer 

Finishing m//l 



Fig. 30. Flow sheet of Minerals Separation oil flotation system, as installed in an 

Alabama mill. 

Simplex System. 

By this system of oil notation, frothing is effected by jets of water 
which impinge on the surface of the pulp. The pulp is fed unclassified to 
the centre of the washer, and the frothing oil is introduced with the water 
from the jets. This water is under a pressure of about 40 pounds per 
square inch. 



100 

The Alabama graphite field is believed to be the only one in which 
this system of oil flotation has been adopted. 

Jaw crustier 

Shak/ng screen. f/2mest)J 



Overs 
S tt/gtj speed ro//s 



TnrougAs 



/^Washer 



Af/dd/ings 
2 nd Washer 



Concentrates 



Ta//mgs 



7b /raste 



Concentrates 



Ta/t/ngs 



3 rc/ fVasner 



Concentrates 
S/r aA/ng screeo/tO O me$t>J 
Overs Ttiroughs 

Dryer 

T 



fin/'sti/ng m/7/ 

Fig. 31. Flow sheet showing Simplex oil notation system, as installed in an Alabama 

graphite mill. . 

Figs. 31 and 32 show a flow sheet of a Simplex installation and a section 
through a Simplex washer, respectively. While data relating to results 
achieved, costs, etc., are lacking, the system is reported to have effected a 
satisfactory concentration. 



FROTHING WATER PLUS OIL 
NOZZLES, '/4' OPENINGS 




SCREEN BAFFL 



TAILINGS SPIGOT 



TAILINGS SPIGOT 



FEED WATER 



Fig. 32. Section through Simplex washer: not drawn to scale. Washer is elliptical, and 
measures about 6 feet by 3^ feet. (United States Bureau of Mines.) 



K. and K. System. 

In 1918, one mill in Pennsylvania was planning the installation of this 
system of oil flotation, but the writer lacks further details. 



101 
Surface Tension or Film Flotation. 

This system of concentration depends on the ability of flat, flaky 
mineral particles to float on the surface of water by surface tension, without 
the addition of oil. This method of concentration has been employed in a 
large number of Alabama mills and is, in fact, practically confined to the 
mills of this State at the present time, though attempts at concentration 
along similar lines were made in Canadian mills a number of years ago. 

The process has the merit of being relatively cheap to operate, the mill 
equipment required is not elaborate, and there are few appliances to suffer 
wear and tear or get out of order. The percentage of recovery by this 
system is, however, not very satisfactory, being probably not more than 
40 to 50 per cent of the graphite in the ore. It is difficult to arrive at 
reliable figures, as few of the mills keep any record of the graphite content 
in the mill feed, and, for one reason or another, some mills effect better 
recovery by this system than do others. The grade of concentrate made 
is claimed to average about 65 per cent graphite. 

Various types of washers, i.e., the tanks in which concentration is 
effected, are employed. That most generally used and the oldest type is 
the Munro washer, or, as it is usually termed in Alabama, the " Ashland 
wet box ". This is a rectangular tank, (Fig. 33) above which is set a feed 



STOCK 
BIN 




BAFFLE BOARD 



WATER FILM e WIDE^ 
COLLECTING LAUNDER ^pflQAL, \ 

FOR CONCENTRATES- 



M 



(~\+~~FEED CYLINDER 

(3 " REVOLVING SHAFT J 



SPREADER PLATE INCLINED 
<50°T0eS°FR0M HORIZONTAL 
lO" LONG 




WATER INLET 



TAILINGS SPIGOT-*]/ 



Fig. 33. Section through original Munro' washer. These washers are built in units about 
4 feet long, placed end to end and back to back. Not drawn to scale; dimensions 
indicated are approximate. (United States Bureau of Mines.) 



cylinder, from which the ore drops onto an inclined spreader plate. A 
baffle board, hung slightly in advance of the point of impact of the ore on 
the spreader, ensures the feed flowing quietly onto the surface of the water. 
On meeting the water, the heavier gangue particles sink to the bottom of 
the washer and are discharged through the tailings vent, while the graphite, 



102 

together with an appreciable amount of fine dust gangue, floats over into 
the collecting launder. These washers are built in units 4 feet in length, 
placed end to end and back to back. 

What is termed the New Munro washer is shown in Fig. 34. This 
consists of a circular tank, into which the feed water is introduced through 



CONICAL SPREADER PLATE 




ANNULAR DPENINO 

^~_Z~_r| ■»{- COLLECTING LAUNOEK 



FOR CONCENTRATES 



TAILINGS SPIGOT 



FEED-WATER PIPE 



Fig. 34. Section through New Munro washer: not drawn to scale. Washer is circular, 
and about 42 inches to 48 inches in diameter; water film is about 12 inches wide. 
(United States Bureau of Mines.) 

a vertical pipe terminating in a funnel whose lip is level with the surface of 
the water in the washer. Slightly above the funnel is set a stationary plate, 
which serves to prevent material falling into and clogging the feed pipe. 
The distance between this plate and the funnel lip can be regulated by set 
screws, so as to increase or diminish the size of the annular opening through 
which the feed water flows. The ore falls onto the surface of the water 
over a conical spreader, and the graphite is carried over the washer lip 
into the concentrates launder by the radial flow of the feed water. 

A third type of washer in common use in Alabama mills is the Colmer. 
This, also, is circular in shape, and much resembles the foregoing in general 
construction. The ore in this case, however, is spread onto the surface of 
the water by means of a revolving disc, the surface of which is ribbed (Fig. 
35). The feed water inlet, also, is situated near the bottom of the tank 
instead of at the surface. The diameter of the washer is about 3J feet, 
giving a water film of about 9 inches, as against 12 inches in the New 
Munro. The revolving disc is designed to feed the ore particles onto the 
surface of the water with a tangential fling, thereby reducing their tendency 
to break the surface film. Some operators claim that better concentrates 
are obtained by keeping the feed disc stationary than when it is revolved, 
so that the superiority of this type of washer over the ordinary wet box 
would not appear to be very pronounced. 

A drawback involved in the use of these washers, and indeed, in any 
system of film flotation, is that the ore needs to be thoroughly dry before 
being fed onto the water film. Rotary, direct heat dryers are generally 
employed in the Alabama field, and the ore is dried either after undergoing 
a preliminary crushing [to about f inch, or, as is more usual, after screening 
to 8-12 mesh, the size at which the ore is fed to the washers. Wood is 



103 

employed for fuel, the consumption being about 3 cords per dryer each 24 
hours. The cost of cordwood delivered at the mills in the Ashland district 
is about $2 . 35 per cord. 



*-FEED PIPC 



CONICAL FEED PLATE 



REVOLVING DISC. 
WATER FILM ABOUT S" WIDE. ^ 
CONCENTRATES 
LAUNOER 




RIQS 





DETAIL OF DISC. 
(ABOUT Id" IN DIAMETER J 



TAILINGS SPIGOT*** 



WATER INLET 



r-SMAFT ATTACHED TO REVOLVING DISC 



Fig. 35. Section through Colmer washer (not drawn to scale). The washer is about 
3 feet in diameter. (United States Bureau of Mines.) 



The graphite content of concentrates made in three mills in the Ashland 
district using the above types of washers was stated to range from 65 to 
80 per cent, the ore carrying 2-5 to 3 per cent. 

Alabama graphite ores are particularly amenable to this method 
of concentration, the flake being thin and light, and, owing to the decom- 
posed nature of the ore, freeing readily from gangue particles. 

On the following pages are shown flow sheets of three Alabama mills 
employing film flotation. In the case of the mill of which Fig. 36 is a 
flow sheet, the cost per pound of graphite of all grades produced during 
the year 1917 was stated to be 4-89 cents. The ore ran about 3 per cent 
graphite and cost 20 cents per ton delivered to the crusher. From a total 
of 31,278 tons of ore milled, 1,222,282 pounds of graphite of all grades 
were recovered. This represents a percentage of recovery of 65 per cent, 
assuming that the run-of-mine averaged 3 per cent graphite. The above 
total was made up as follows : — 



No. 1 flake, 87 per cent carbon, 
No. 2 flake, 82 per cent carbon, 
Dust, 42 per cent carbon, 



656,100 pounds or 
150,380 pounds or 
415,802 pounds or 



53-7 per cent. 
12-3 per cent. 
34-1 per cent. 



1,222,282 pounds or 100-0 per cent 



67945-8 



104 



According to information furnished by the management, the mill shown 
in Fig. 37 treats a 3 per cent ore, and effects a recovery of 60 per cent of the 
graphite in the ore. The mill has a capacity of 150 tons of ore 

Jaiv crusher 
Mul/er pan, -fitted w/th % grate 

Rotary dryer,(d/rect heat 4'*3sj 
Screen (8 mesh ) 

I | 

Overs Throughs 

AT/Ro/fs 
Screen (8 mesh) 



Overs 



Overs 
AT 2 Ro//s 
Screen (/2 mes h) 



Throughs 



. Taitinxs 



Throughs 



IVasher feed bin 



r 

Zaihhgs- 



Washers 



Munro type 

Concentrates 
Detvatering screen (30 mesh) 



Rotary dryer (indirect heat) 
C/ass/fy/n£ fan 



Sand taihngs 



Concentrates 



Sea/per (flour mi// type) 



r 

N°/ 



AY? /mi// stock 

Buhrsfone 

Sea/pe r 



T 

AF2 



Dust/V?, 



/\/?2mi//stocA: 

Buhrstone 

I 
Sea/per 



Dust 



/V?2 



Dust 
\ 



Screen f60m esh) Screen (/00 m esh) 



Overs 



m 



j 

Overs' 

J 



7hroughs 



NVf/ake 



N°2f/ake 



Dust 



Fig. 36. 



Flow sheet of surface tension concentration installation, using Munro washers, 
in an Alabama mill. 



per 24 hours and employs 11 men to a shift. Ore is delivered to the 
crusher for 20 cents a ton, and the cost of production of finished graphite 
of all grades averages 4J cents per pound. The proportion of the different 
grades made is: — 

No. 1 flake, 90 per cent carbon, 60 per cent. 
No. 2 flake, 85 per cent carbon, 20 per cent. 
Dust, 44 per cent carbon, 20 per cent. 



105 



Jaw crusher 

Mutter pan 

Rotary dryer 

Screen (/2 mesh) 

I 1 

Ovens ThrougAs 



Overs 
-4-J 



fto//s 

Screen (/2mesh) 



Throughs 

-<r— 



Washer feed bin 



/6 M ashers, Munro type w/t/> r o/fer feed 



Concentrates 

2 deiyater/ng ta6/es 
(SOmesAJ 

Drying f/oor (Steam pipes) 



Tai/ings 



/fee/ (60 mesh) 



Overs 
Air c/assif/er 



Throughs 
Air c/assif/er 



r — i r r~7 

Concentraies M/dd/ings 7ai/ings Concentrates Middhngs Tailings 

— i r f \ ■ >. L 



/fee/ (40 mesh) 
Overs Throughs 

-J 4 /' r 

Air c/ ass/f/er 
Concentrates M/dd/ings Tai/ings 



Bags 



Ro//s 
ftee/(60mes/i) 

Overs Through, 

— « — I 



Dedusterf/25 m esh) 
Overs Throughs 

I L__ 

Sizer, 30 mesh 



Overs 
Buhrstone 



Throughs 
Buhrstone 



D eduster (/ 25 mes h) /)eduster(/2Smes h) 
Overs Throughs O/ers Throughs 



S;zer (90 mesh J 

I 1 

Overs Throughs 



N°/f/ake 



hl°2f/ake 



Dust 



Fig. 37. Flow sheet of surface tension concentration installation, using Munro washers, 

in an Alabama mill. 
67945—8* 



106 



Only about 50 per cent of the total concentrates made passes to the 
burrstones. 

This mill, in common with practically all of the mills in the Alabama 
field, employs electric power, which costs 3 cents per K.W.H. up to a 
minimum consumption, and 0-6 cents per K.W.H. over this, or $33 per 
H.P. year. The plant is equipped with three motors of 100, 75, and 
50 H.P. respectively, which operate the mill machinery, pump, lighting 
installation and haulage system from pit to mill. 

At another mill in the same district, equipped on similar lines to that 
described above, but using, in addition, the air separator described above 
to eliminate the heavy gangue particles from the feed for the washers, the 
following amounts of graphite of various grades were obtained from a 
total of 123,950 pounds of concentrates running 65-5 per cent carbon. 

No. 1 flake, 92-8 per cent carbon, 62,850 pounds or 50-7 per cent. 

Special dust, 60 per cent carbon, 11,600 pounds or 9-4 per cent. 

Regular dust, 30 per cent carbon, 49,500 pounds or 39-9 per cent. 



123,950 pounds or 100-0 per cent. 

At the mill using flow sheet, Fig. 38, it was claimed that the concen- 
trates from the Colmer washers ran 75-80 per cent carbon, and that the 
No. 1 flake went as high as 92 per cent. This mill has a capacity of 100 
tons of ore per 10 hours and employs 10 men. 

While concentration of graphite by surface tension or film flotation 
is practically confined to the Alabama field at the present time, it is 
noteworthy that the method was practised in mills in the Buckingham 
district, in Canada, as far back as 1901. In that year, H. P. Brumell, 
of Buckingham, patented 1 a device (Brumell's wet box) which is to all 
intents and purposes identical with the Munro type of washer now 
employed in Alabama. The appliance was installed in several mills in the 
Buckingham district and is said to have effected a satisfactory concentra- 
tion. The fact that Canadian ores usually carry a large proportion of 
mica, much of which floats off with the graphite, may have been the cause 
of the device being discarded. 

Experiments are being conducted at the present time by the Depart- 
ment of Mining Engineering, University of Toronto, with a system of film 
flotation by which the ore has a small amount of coal oil added to it and 
is fed wet to the washer. 2 

Below are shown the results of assays 3 made on the three grades of 
product turned out by a mill in the Buckingham district, Que., using 
Brumell wet boxes for concentrating, the concentrates being afterwards 
cleaned on burrstones: — 





No. 1. 


No. 2. 


Dust. 




Carbon 


93-87 
301 
1-33 
1-35 
0-20 
•24 


91-77 
411 
1-98 
1-74 
0-10 
0-30 


71-82 


Silica 


15-80 


Alumina 


7-64 


Ferric oxide 


310 


Alkalies 


0-64 


Lime 


100 








100-00 


100-00 


100 00 



1 United States patent No. 678,860, July 23, 1901. 

2 Preliminary Report of an Investigation into the Concentration of Graphite from some Ontario 
Ores, Can. Min. Journ., March 26th, 1919, pp. 189-97. 

3 Assays by Dunstan, Birmingham, England. 



107 



C/tamp/on crvsAer 
Screen (/" mes/t) 



Overs 
Jatv crusher 



Throughs 



ftotary dryer (d/rect /teat) 



+4>/nch 
Hough/ ng ro//s 

— I 



Wh/ptap screen 



Af/ddhngs 
F/ne ro//s 



-/6 mesh 
4/r c/ass/f/er 

f/ne sand Heai 



JL 



r *- 

Dust ho//ector 
h/ewaygo screen {/OOme shJ 



Dust fine sane/ Heavy sand 



7b tvaste 



Thrdughs 



Overs 



j 



fVasher feed 6/n 
70 Washers. Cofmer typ e 
Tai/ings 



Concentrates 



Jig ivash/ng screen 
° (/OQmesh) 



I 7b tvaste y 



Overs 
Dra/n/ng f/oor 
Drying pan, steam Aeatect 



~1 

Throughs 



7b tvaste 



Sea/per 

Aspirator 



7b tvaste 



Dust 



Flake Heavy sand ' , 
with attached f/ake 

Hoiis 

I ^_ 



S/zer 



Buhrstone 



Sizer 



AP/ H 9 2 



Dust 



Buhrstone Buhrstone 

J J 

S/zer S/ze r 

A N*2 Dust AF/ /V?< 



V Dust 



Fig. 38. Flow sheet of surface tension flotation installation, using Colmer washers, in an 

Alabama mill. 



108 

Composition of ash, calculated from above :— 

Silica 51-88 

Alumina 23-79 

Ferric oxide 17-68 

Alkalies 2-91 

Lime 3-74 



100-00 

MISCELLANEOUS. 

A modified system of film flotation has lately been installed in several 
Canadian mills. Details of operation of this process are not divulged, and 
its success has not yet been demonstrated. It is understood that the 
ore is ground in a ball mill, with the addition of a small quantity of 
petroleum. The pulp is then classified by a patented device and flows 
onto the surface of water in a washer or cell, the graphite flakes being 
carried over a lip and the gangue sinking. It is claimed that, in this way, 
a concentrate of very high purity is obtained. 

A system of concentration that is believed to have been adopted 
extensively in Germany is that introduced in 1903 into the graphite mills 
of the Passau district, in Bavaria. This process, patented by H. Putz, 
consisted m mixing the raw graphite with petroleum and water, in the 
proportion of 1 part of oil to 2-3 parts of water, the mixing taking place 
in a mill of the burr type or between rolls. After sufficient grinding, the 
mixture of graphite and oil passed to a cylinder containing a larger amount 
of oil and water, in which it was thoroughly worked up, the graphite 
flakes separating from the sand and clay and remaining on the surface, 
while the gangue sank and was taken off through an opening in the cylinder. 
The graphite passing off with the overflow from the cylinder was caught in 
a tank, in which a wire screen was fixed some 6 inches below the surface 
of the water. The purpose of this screen was to catch the small aggregates 
of graphite flakes which surface tension did not suffice to suspend. On 
stirring the liquid, these aggregates broke up and the component flakes 
rose to the surface. The graphite pulp remaining in the cylinder was 
drawn off into a similar tank. By repeating the above process a sufficient 
number of times, according to the character of the ore, a product of high 
purity was obtained. The larger sand particles, which often carried 
graphite attached to them, were screened out from the tailings and returned 
to the circuit. The initial removal of the oil from the graphite was accom- 
plished by means of a filter bag or a fine mesh wire container suspended 
in water, after which the graphite passed to a press to remove water, 
the remaining oil being then got rid of by distillation. The foregoing 
process was designed particularly to treat the more earthy, soft graphites, 
but by a series of modifications, involving chiefly a preliminary grinding 
in chaser mills, was made applicable also to the harder, unweathered 
graphite-gneiss of the district. In the above process, there was no attempt 
made to create a froth, as in the modern systems of oil flotation proper, 
the separation of graphite from gangue being accomplished by coating 
the former with oil. 

A system of cleaning graphite by means of petroleum, similar to 
that described above, has been practised for some years at a small plant 
near Chester Springs, Pennsylvania. The material cleaned consists 
mainly of low grade dust graphite from crucible works and graphite mills. 



109 

The efficacy of petroleum or similar oils in any wet system of graphite 
concentration has long been known, and it has been a common practice to 
make the addition of small amounts of such oils to the graphite and water 
pulp at some stage of the various concentrating processes used, thereby 
often materially increasing recovery. Some wet installations, indeed, 
may be said to have depended on the addition of oil for their successful 
operation. In such cases, however, the amount of oil added was so small 
as not to necessitate its removal from the finished product by the agency 
of heat or by other special means, washing of the concentrates on reels 
with either warm or cold water sufficing. 

A means of converting the fine graphite dust or slimes resulting 
unavoidably from almost all milling and concentrating processes to a 
product suitable for crucibles, lubricating, etc., has also been devised 
by H. Putz, and is reported to have found successful adoption in the 
Passau district. Many of the graphites of this region could not be treated 
by the above oil process, owing to the fineness of the flake, much of which 
passed through the screens with the sand slimes. To obviate this, the 
crude graphite was first passed through sets of rolls, either with or with- 
out the addition of some bonding substance, such as powdered pitch, 
asphalt, paraffin, etc. The material may be heated or not, according 
to requirements. As a result of this process, 1 the fine flakes are pressed 
into larger aggregates and these latter are then broken up and sized by 
screening. The more compact the aggregates are made, that is the 
greater the pressure exerted by the rolls, the more refractory is the result- 
ing material. Even amorphous graphite can, it is claimed, be converted 
into marketable flake by the above means. Whether this class of material 
can be used as satisfactorily in crucible work as the natural flake is open 
to question, however, and the raw material must in any case undergo 
some cleaning process to remove the impurities that are almost invariably 
present in natural graphites. It is reported, however, that such built-up 
flake has been extensively employed for crucible manufacture in Germany 
during the last few years. 

Experimental work on the briquetting of flake graphites has recently 
been carried out by R. T. Stull and H. G. Schurecht, of the United States 
Bureau of Mines. 2 In the experiments undertaken, an attempt was 
made to convert Alabama flake graphite to a granular form by briquetting 
it with tar, coking, crushing and screening. In this way it was hoped 
to secure a denser material that would approximate Ceylon plumbago in 
character and be the equal of the latter for crucible work. Varying propor- 
tions of tar binder were used, and briquetting was effected at different pres- 
sures. In testing the graphite prepared in this manner in crucible bodies, 
alongside of ordinary Alabama flake and Ceylon plumbago, it was found that 
the best crucible's, as far as moulding properties were concerned, were made 
with the prepared graphite. In foundry use, however, the all-flake 
crucibles proved to give better service than the prepared graphite pots, 
and both proved superior to pots made with straight Ceylon plumbago. 
The investigators' comment on the experiments is that the results are 
interesting, but not conclusive, as only four crucibles of each mix were 
tested. 



1 German patent No. 161,722. 

2 Journ. Amer. Ceramic Soc, May 1919, pp. 391-9; also March, 1919, p. 208. 



110 
Refining of Graphite Concentrates. 

By most of the methods hitherto employed, it has proved impractic- 
able to raise the carbon content of graphite concentrates to much over 
60 — 70 per cent, and it has been necessary to refine or finish the concent- 
rates, with the object of separating as far as possible the remaining 20 — 30 
per cent of gangue from the large flake and concentrating it in the fine 
dust product. It has thus been customary to regard the milling process 
as divided into two stages: the concentrating, wherein a progressive 
elimination of gangue is effected; and the finishing, which achieves no 
further removal of gangue, but concentrates as much of it as possible in 
the fines. Many of the flow sheets given on preceding pages include both 
concentrating and finishing departments. 

Recent developments in oil flotation concentration indicate the 
possibility of making concentrates sufficiently high in carbon as not to 
require any further cleaning, so that in this case a separate finishing de- 
partment may be regarded as eliminated. The same holds good in some 
cases where electrostatic separators are used, since these machines are 
really concentrators and function by throwing out mechanically admixed 
gangue: on certain ores, especially weathered ones, the resulting concen- 
trates may be sufficiently clean to be marketed without any finishing. 

For refining, the concentrates must be dry, and where wet methods of 
concentrating are employed, this necessitates the use of some style of 
dryer. The dryer most generally used is the rotary, direct heat type. 
This machine has the advantage of large capacity, and being automatic in 
its operation, no handling of the concentrates is required. In some mills, 
pan dryers, heated by steam pipes, are used. In one Quebec mill the 
concentrates are shovelled on to trays, which are placed in tiers in a steel 
frame, and the latter is run into a drying chamber. 

Before drying, the concentrates usually have the surplus water removed. 
In Pennsylvania and Alabama mills, this is effected by passing the material 
over de-watering screens, as well as by allowing the overs from the washing 
reels to accumulate on inclined cement floors, where the water auto- 
matically drains out. In an Ontario mill, using buddle concentration, 
the slimes contained in the overflow are de-watered in a filter press. An 
Alabama mill employing oil flotation, uses an Oliver filter, in conjunction 
with a Dorr thickener, for de-watering the concentrates from the cleaner 
cells, and a vacuum type filter is used in a Quebec mill. 

The most general method of finishing graphite concentrates is to 
pass them over burrstones, followed by screens. In place of burrs, 
closely set polishing rolls are sometimes employed. The purpose of both 
burrs and rolls is the same, namely to subject the graphite flakes to suffi- 
cient pressure to pulverize the fine gangue included between the laminae, 
as well as to remove any mechanically admixed gangue particles. With 
burrs, considerable care is necessary in setting the stones at the correct 
interval to pulverize the gangue and at the same time to avoid undue 
destruction of the graphite flakes. The burrstone mills used are of hori- 
zontal type, and as a general thing it is the lower stone that revolves. In 
this way, only the grit particles are broken down, while the graphite 
flakes pass through without being subjected to the weight of the upper 
stone. The stones are very lightly dressed, having relatively few and 
shallow furrows. 



Ill 

Polishing rolls in place of burrs are employed in a few cases, but 
their use has been practically confined to Canadian mills. The rolls 
used are of the same type as shown in Plate XXXI. One Quebec mill 
uses a Seek polisher, of German manufacture. (Plate XXXVII.) 

After passing through the burrs or rolls, the product is screened, 
usually over 90 and 150-mesh screens, these yielding the three commercial 
grades of graphite, No. 1 flake (+90 mesh), No. 2 flake ( — 90 + 150 mesh) 
and dust ( — 150 mesh). 

Summary. 

While maximum extraction and purity (carbon content) of the finished 
graphite are prime essentials in the successful operation of a graphite 
mill, an equally important factor is the proportion of graphite recovered 
in the form of No. 1 (+90 mesh) flake. 

By practically all mechanical methods of treatment, high carbon 
content and largeness of flake are concomitant within limits; that is, 
after grinding has proceeded sufficiently far to free the large flake of 
attached gangue. 

Many of the processes hitherto employed have succeeded in making 
finished products of satisfactory purity only at the expense of extraction. 
The difficulties attending the concentrating of graphite ores may be gauged 
to some extent from the flow sheets given on the preceding pages, which 
show the variety of methods that have been employed in different mills. 
With the exception of oil flotation, few, if any, of the systems outlined have 
been consistently successful in making concentrates assaying more than 
60 to 65 per cent carbon, with an extraction of much over 50 per cent. 

In the above connexion, the following data 1 are quoted to show the 
average results obtained in Alabama mills during 1918: — 



Material. 


Carbon, 
per cent. 


Weight, 
pounds. 


Weight X 
per cent. 


Recovery 
or loss, 
per cent. 


No. 1 flake 


87 
77 
30 

1-46 
2-5 


19 
5 
3 


1,653 

385 

90 


33-06 


No. 2 flake 


7-70 


Dust 


1-80 






Total 


27 
1,973 


2,128 
2,872 


42-56 


Tails, by difference 


57-44 








2,000 


5,000 


100 00 







Important considerations to be noted in connexion with the treat- 
ment of graphite ores include the following: — 

(a) Subjection of the ore to the least possible degree of coarse grinding 
consistent with maximum extraction of large flake. The choice of the 
grinding machine best adapted to any particular ore is important. Wet 
grinding in ball mills, stamps, muller pans, etc., achieves this by allowing 
the flake to float off as soon as freed. 

(b) Separation, after successive grindings, of larger graphite flakes 
from gangue particles, in order to prevent the latter cutting and destroying 
the flake during passage through the next machine. 

1 Dub, G. D., op. cit., p. 11. 



112 

(c) Elimination of fine dust or slimes from the ground material as 
soon as made. Fine gangue particles have a tendency to be pressed 
into the flakes by the grinding machines, forming what are known as 
pancakes. 

• 
Chemical Refining of Gkaphite. 

While the refining of graphite to a degree of purity sufficient for most 
commercial purposes (90 per cent carbon) can be effected by mechanical 
means, the complete elimination of mineral impurities often present in a 
very fine state of division, such as silica and iron sulphides and oxide, can 
only be achieved by chemical treatment. These substances are often 
present in a state of microscopic fineness, intimately intergrown with the 
graphite, and thus cannot be removed without reducing the flakes to 
powder; in which form the graphite loses most of its value for such purposes 
as crucibles and lubricants. However, for some special purposes, it is 
desirable to have extremely pure graphite, even at the expense of the 
flake size, and to this end a number of methods of chemical refining have 
been proposed and in some cases actually employed in commercial practice. 
The advent of cheap artificial graphite, which can be produced in a degree 
of purity approaching practically pure carbon, has largely dispensed with 
any necessity for chemically refining natural graphite; but the following 
details of the more important methods that have been devised for such 
chemical treatment may be of interest. No one process is applicable 
to all graphites, since the impurities present v&ry considerably in different 
ores. 

Schlossel treats graphite with hydrochloric acid, followed by caustic 
soda, afterwards heating with sodium carbonate and washing in warm 
water. The caustic soda tieatment would appear to be superfluous, 
and the hydrochloiic acid might be employed to greater advantage at the 
end of the operation than at the beginning. 

Winkler mixed finely ground graphite with a mixture of equal parts 
of calcined sodium carbonate and sulphur and heated at a low red heat 
in a crucible till all the sulphur was burnt off. The cooled mass was then 
boiled in water and washed by decanting, the residue being treated with 
dilute hydrochloric acid, which removed the iron present. After washing, 
the residue was ignited, and the silica removed by boiling in a solution 
of caustic soda. 

Brodie's process, alluded to elsewhere, 1 may be included here, though 
its chief aim was to produce a very finely divided, rather than a specially 
pure graphite. Powdered graphite is mixed with one-fourteenth of its 
weight of potassium chlorate, and is then stirred into an iron vessel with 
a weight of concentrated sulphuric acid equal to twice that of the graphite. 
The whole is then heated on a water bath until action ceases. After 
cooling, the residue is washed in water, dried and heated to a red heat, 
whereupon the graphite swells up and crumbles to an extremely fine 
powder. This powder may then be further cleaned by elutriation. This 
process is specially adapted to Ceylon graphite. If silicates are present 
in any amount, sodium fluoride is added to the mixture, and the silica 
thus passes off as fluoride. 

Pritchard takes 18 parts by weight of graphite, 1 part of potassium 
chlorate, and 36 parts concentrated sulphuric acid, heats the mixture 

1 See page 7. 



113 

till all chlorinated vapour is driven off, pours off the remaining acid 
and adds a small amount of sodium fluoride to the graphite. This is then 
washed and heated to red heat. 

Brochadon takes finely powdered graphite and fuses with sodium 
carbonate, washes with water, followed by hydrochloric acid, and again 
with water. After drying, a soft, powdery graphite is obtained, which 
when moistened can be pressed into blocks by hydraulic pressure. These 
blocks have all the appearance, hardness, etc., of natural graphite, but 
possess an electrical conductivity eighteen times that of natural graphite. 

What was essentially a forerunner of present day oil flotation, and 
should, therefore, perhaps be more properly classed as a mechanical 
process, was patented by Bessell Bros., in Germany, in 1887. They 
mixed graphite with from 1 to 10 per cent of an organic substance, such 
as petroleum, benzine, fat or wax, and stirred the mixture into water at 
30-40°C. A current of gas was then generated in the pulp by adding 
chalk or some other substance and introducing a dilute acid. The particles 
of graphite were thereby brought to the surface, while the impurities 
sank. A graphite containing 40 per cent carbon could be refined to 90 per 
cent by this process. 

Luzi's process of refining consisted in moistening graphite with concen- 
trated nitric acid and igniting. The graphite thereupon exfoliates into 
peculiar, vermiculate forms (see p. 7), and the impurities present between 
the laminae are released and can be readily removed by washing. The 
heating is carried out in retorts, and the acid recovered. The graphite 
obtained by this process is remarkably plastic and can be readily pressed 
into blocks or plates. 

A process used commercially by Douglas Bros., in Germany, in recent 
years, consists in treating graphite with an aqueous solution of hydro- 
fluoric acid, thereby converting the accessory mineral impurities into 
fluorides. These fluorides are then removed by the addition of a solution 
of sodium bisulphate, which converts them into salts soluble in water, 
followed by washing with water. 



114 



CHAPTER VI. 

ARTIFICIAL GRAPHITE. 

Graphite is made commercially on a very large scale by the Acheson 
Graphite Company, of Niagara Falls and Buffalo. The original discovery 
that graphite could be produced in the electric furnace was made in the 
course of experimenting with the effect of very high temperatures on 
carborundum. It was found that carborundum is decomposed at about 
7500°F, the silicon being vaporized and the carbon left behind. A process 
was eventually developed for making graphite from anthracite coal. 
The powdered coal is heated for several hours in the furnace, and the 
carbon is first of all converted into carbides of the various constituents 
of the ash. On carrying the temperatures still higher, these carbides are 
decomposed, and the silicon, iron and aluminium vaporized, the residue 
being a graphite free from all trace of amorphous carbon. The purity 
of the graphite depends on the temperature reached in the furnace. After 
removal from the furnace, the graphite is ground to the varying degrees 
of fineness required for the different uses to which it is to be put. In 
some cases it is air floated, and for the production of high grade lubricating 
compounds deflocculated (see below). 

The following details of the methods of manufacture and properties 
of Acheson artificial graphite are taken from a paper by Dr. Edward 
Acheson. 1 The first commercial graphite was produced in 1897, when 
162,000 pounds of graphite electrodes were made. These electrodes 
were produced by the direct conversion of non-graphitic carbon rods, 
made from a mixture of petroleum coke with tar as a binder, into graphite. 
About the same time, the manufacture of graphite in powder form was 
undertaken, the raw material being anthracite coal, and even coal waste 
or culm. This material is crushed fine and placed in the furnace, which 
is of long, narrow, trough-like form with an electrode at either end. On 
the passing of the current, innumerable small arcs are formed between 
adjacent particles, and the mass becomes incandescent and is allowed 
to remain so until all the impurities have been vaporized, the length 
of time required being dependent on the purity of the raw material. The 
temperature reached is in the neighbourhood of 7,500°F. 

A guaranteed purity of 99 per cent carbon is claimed for this graphite. 
For lubricating purposes, it is ground to 200 mesh, and this fine material 
is still further reduced, for the purpose of suspending it in oil or water, 
by what is termed the deflocculating process (see page 158). In preparing 
this deflocculated graphite for practical use, it is first diluted with water, 
and the mixture is run into large settling tanks where it remains four days. 
It is then decanted and passed through a filter press fitted with rubberized 
canvas sheets. In this way, a paste is obtained consisting of about 50 per 
cent graphite and 50 per cent water. In order to replace the water by oil, 
the paste is placed in a pug mill, and small additions of oil are made, until 
eventually the water is completely replaced by oil. This paste of graphite 
and oil, mixed with kerosene, yields the Acheson lubricating product 

1 Paper read before the National Gas and Gasoline Engine Trades Association, in Cincinnati, 
June 14th, 1910. Issued in booklet form by the Acheson Graphite Company. 



115 

known as "Oildag", while a mixture of water with the paste of graphite 
and water is termed "Aquadag". 

The combined production of Acheson artificial graphite in 1917 
at both the company's American and Canadian works totalled 5,785 short 
tons. This represents only the graphite that comes into competition with 
natural graphite and does not include graphitized products, such as elec- 
trodes. 

Artificial graphite is not suitable for use in graphite crucibles, but is 
recommended for many of the uses to which natural graphite is put, such 
as lubricants, paints, boiler graphite, dry battery filler, pencils, etc. 

Dr. Acheson 1 says, further, regarding the defloceulation process: — 

The effect was produced by treating the graphite in the disintegrated (ground) form with 
a water solution of tannin, the amount of tannin being from three to six per cent by weight 
of the graphite treated. The results are much more pronounced when the mass of graphite, 
water and tannin has been pugged or masticated for a considerable time, I having to advan- 
tage carried on this process continuously, without interruption, for a period of one month. 
I have also found that while the effect may be produced in a very satisfactory way with 
distilled water, the waters as found in rivers, deep wells, etc., are improved by the addition 
of a trace of ammonia. The presence of carbon dioxide in the water will prevent defloc- 
eulation. 

If water, graphite, a drop of ammonia and a little gallo-tannic acid be shaken up 
together in a test tube, enough of the graphite will remain suspended in the liquid to give 
it a black colour. Most of it, however, will settle, and to cause a complete suspension 
of all the graphite necessitates prolonged mastication in the form of a paste with the 
water and tannin. I find that after this mastication has been carried out, the effect 
is very much improved by diluting the mass with considerable water and allowing it to 
remain some weeks with occasional stirring. 

After the prolonged masticating and additional time of exposure of the graphite 
to the water and tannin, an intensively black liquid is obtained consisting of water, a 
small amount of tannin, and graphite; the latter may be present in varying amounts. 
In this condition, I call the graphite deflocculated, a state of subdivision much finer than 
possible of attainment by mechanical means, one that may perhaps be correctly spoken 
of as molecular. It is in that condition called colloidal. I have found this liquid would 
pass through the finest of filter papers and the contained graphite would remain in 
suspension for weeks and months, — apparently for all time. 2 One per cent of graphite 
makes the liquid so thick that it runs through the filter paper slowly. Reduced to 0-2 of 
one per cent, it goes through quickly 

I have found that the addition of a very minute amount of hydrochloric acid causes 
the contained graphite to flocculate, i.e. group the molecules into masses so that it will 
no longer pass through the paper. 

This graphite, even after such flocculation, is so fine in its particles that when dried 
en masse it forms a hard article. It is self-bonding, like a sun dried clod of clay. 

For further details of the technology of artificial graphite see 
Journal of the Franklin Institute, Vol. CLIV, 1902, pp. 321-348. 

The following extracts are taken from a monograph 3 on artificial 
graphite by A. J. Fitzgerald, chemist to the International Graphite 
Company, Niagara Falls: — 

If carbon, in the form in which it usually occurs in nature and in general use, is to be 
altered to graphite by heating in the electric furnace, it is a natural assumption that the 
higher the carbon content of the charge is, the greater will be the amount of graphite 
obtained. This would be the case, provided that the carbon were altered directly to 
graphite, but I have found that such an alteration does not take place and that in actual 
practice it is not advisable to heat carbon very highly, since the amount of graphite that 
results is small. What actually occurs in making graphite out of coal is an indirect altera- 
tion, consisting in a disassociation of the compounds of carbon with other substances 
(carbides). The first stage of the process consists, therefore, in the combination of carbon 
with such other substances, and I have found that the quantity of graphite obtained 
is considerably greater and a better product is secured, when a coal is used that contains 

1 Journ. Franklin Inst., Vol. CLXIV, 1907, p. 376. 

2 Cf. C. H. Bierbaum's remarks on Brownian movements in such liquids, p. 156. 

3 Monographien Uber Angewandte Elektrochemie, Vol. XV, Halle, 1904. 



116 

a considerable amount of foreign mineral substance, or when a certain proportion of such 
mineral substance (silica, clay, alumina, lime, iron oxide) is mixed with the coal. 

Acheson's experiments showed that a relatively small amount of such carbide- 
forming substances can bring about the alteration of a large quantity of carbon into 
graphite, and that this amount is much less than is theoretically necessary to convert 
all the carbon into carbides. For example, an anthracite coal containing 5-78 per cent 
ash, the composition of which was essentially silica, alumina and iron oxide, is converted 
into practically pure graphite containing only 0-03 per cent ash. 

The furnace used is of the. same general type as that used in the production of 
carborundum, but is preferably a little smaller in diameter. It is lined with carborundum 
as a refractory. The charge consists of pulverized anthracite, or even culm, which is 
packed around a central core of carbon rods. These rods lie in close contact and extend 
the length of the furnace. This core of rods is connected with the electrode at either end 
and its purpose is to serve as a conductor for the current during the initial stage of the 
process. 

After the furnace has been filled with coal, a covering of sand and coke is laid over 
the charge, in order to exclude air. 

A furnace 30 feet long and taking a charge of 20" x 14" section will consume 800 k.w. 

As the coal becomes graphitized, that is, with increasing temperature and conduc- 
tivity of the charge, the voltage is reduced. The length of time that the heating is 
allowed to continue depends on the degree of purity of the graphite required. For most 
purposes, a purity of about 90 per cent carbon is sufficient. Where a very pure graphite 
is required, however, the heating is continued until practically all the impurities have 
been volatilized. 

After cutting off the current, the sand and coke cover is removed, and the layer 
of carbide exposed that forms directly over the graphite. At this stage, the furnace is still 
white hot. After it has cooled down sufficiently, the carbide layer is removed and finally 
the graphite is taken out, and ground up for the various purposes for which it is required. 

In Fig. 39 is shown the general form of an electric furnace for the 
production of graphite. 



^®S 




Fig. 39. Section through electric furnace for the production of artificial graphite. 

2, electrodes; 3, core of powdered coal; 4, mixture of powdered coal or coke and 

sand; D, source of energy. 

The manufacture of electrodes is carried out in the usual manner, except that a 
definite amount of carbide-forming substance is added to the material. The carbon 
or petroleum coke is first finely powdered, and is then intimately mixed with pitch, a small 
quantity of a carbide-forming substance, such as oxide of iron, in the form of fine powder, 
being added. The mixture is then warmed and fed in the form of blocks to the extruding 
machine, which presses out rods of the desired size and form. These rods are baked and 
are then ready to be graphitized. The latter operation is conducted in a furnace of the 
types shown in Figs. 40 and 41, the former being used for electrodes of rectangular section 
and the latter for round rods. The floor of the furnace is covered with a thin layer of 
pulverized coal upon which the electrodes are stacked, with their long axes at right angles 
to the long axis of the furnace. The piles of electrodes are separated by gaps about 
one-fifth the width of an individual electrode. Sheet iron is then placed in the furnace 
for its entire length, and at a distance of about one inch from the ends of the electrodes 
and the side walls of the furnace. In this way, a sort of double walled box is formed. 
The inner shell is filled with ground coke of about 2 mm. grain, while in the outer is placed 
a mixture of sand and ground coke. The inner shell is filled up with coke until the upper- 



117 



most electrode is covered about 2 inches deep, 
upper part of the furnace covered over with 
current is turned on. 



The sheet iron is then removed, and the 
the sand-coke mixture, after which the 



/*&<■ 




Fig. 40. Section through electric furnace arranged for graphitizing carbon electrodes of 

rectangular section, a, brick base; b, end walls; c, electrodes; d, connexions to 

source of energy d'; e, electrode charge; g, layer of powdered coal or coke; 

h, refractory lining; i, covering of sand and powdered coke. 

As shown in Fig. 41, the furnace used for round rods is similar to that for those 
of rectangular sections, only in stacking the electrodes, they are placed in close contact, 
instead of in heaps separated by gaps. 



^&^ 



I 




Fig. 41 . Section through electric furnace arranged for graphitizing round carbon electrodes. 

a, brick base; b, end walls; c, electrodes; d, connexion to source of energy d'; 

e, electrode charge; g, layer of powdered coal or coke; h, refractory 

lining; i, covering of sand and powdered coke. 

The process of graphitizing is the same as in the production of powdery graphite. 
The initial voltage used is 200 at which point it is kept until 73b k.w. are registered. Then, 
as the resistance sinks, the voltage is cut down proportionately, so as to keep the power 
consumption a constant. The resistance at first sinks very rapidly but gradually the 
rate slows down until it finally becomes constant. The alteration to graphite is now 
complete. 

In considering the theory of the graphitizing of electrodes, the following points are 
of importance. A definite number of electrodes are required to be heated to a definite 
temperature, in order to graphiti?e them. To this end, a definite amount of electrical 



118 

energy must be transformed into heat in the furnace. This heat is consumed in a variety 
of ways: to bring the charge of electrodes to the required final temperature; to form 
carbides; to decompose these carbides and volatilize the carbide-forming substances; 
to replace the heat absorbed from the charge by the furnace walls and lining and that 
lost by radiation. It is thus a matter of experiment to determine the amount of electrodes 
that can be treated in actual practice. In proportion as the temperature of the furnace 
increases, so does the loss through radiation, and the larger the furnace, the longer it takes 
to reach the desired temperature, so that a point is eventually reached where an increase 
of dimensions is no longer economically practicable. In this connexion, the resistance 
of the furnace must also be taken into consideration. 

In graphitizing electrodes having a rectangular section, the resistance of the furnace 
would soon sink very low if the electrodes were all stacked in close contact, and it is for 
this reason that they are packed in heaps separated by pulverized coke, which has a much 
higher resistance than the electrodes. It can readily be seen, when the furnace is running, 
how the heat energy is chiefly developed in the coke that separates the electrodes and 
serves to heat them up. In the case of round electrodes, the contact surface between 
individual rods is very small, and the resistance is consequently high enough for practical 
operation. 

With regard to the properties of Acheson graphite, the writer goes on 
to say: — 

The alteration of carbon to graphite is a complete one; that is, when treated with potas- 
sium chlorate and nitric acid, no trace of amorphous carbon is found. But, with respect to 
the above test, and also to Berthelot's definition of what constitutes graphite, i.e., a form 
of carbon that yields graphitic acid on oxidizing at a low temperature, it should be noted 
that all graphite, made in the above described manner, but from various materials, does 
not exhibit the same characteristics. For instance, electrodes made from soft coal and 
petroleum coke respectively, show decided differences in their properties. The former 
are hard and brittle, mark paper with difficulty and do not become shiny on rubbing; 
when ignited in air they are soon consumed, and when used as anodes in the electrolysis 
of sulphuric acid, their decomposition is rapid. Petroleum coke electrodes, on the other 
hand, possess the reverse of all the above characteristics. The specific gravity, also, 
is 2-05 for the former, as against 2-20 for the latter. According to Berthelot's definition, 
both the above are graphite, yet they are decidedly different in most of their physical 
properties. It appears useless to attempt to prescribe a descriptive nomenclature for all 
the different modifications of carbon, since the diversity of forms in which amorphous 
carbon and graphite occur seems to be limitless. Even the expressions used to distinguish 
the forms of carbon that yield graphitic acid from those that do not — namely, graphite 
and amorphous carbon, do not correspond to fact. A number of natural graphites are 
amorphous, while many of the artificial types possess crystalline structure. The graphite 
formed by the decomposition of carborundum, for instance, appears to be finely crystalline 
but is really amorphous. Graphites made from anthracite coal are very variable in their 
character, corresponding to the grade of coal used. Some are soft and lustrous, others 
hard and matt. The general range of specific gravity is between 2-20 and 2-25, and all 
the types burn in air more readily than Ceylon graphite, though they are more resistant 
to the action of potassium chlorate and nitric acid than the latter. 

Graphite made from anthracite 1 is used chiefly as a paint pigment, in dry batteries, 
graphite brushes, etc., while that made from petroleum coke, and containing less than 
2 per cent ash, is employed in lubricants, pencils and other articles requiring a very clean 
graphite. 

1 See also W. C. Arsem, Transformation of Other Forms of Carbon into Graphite. Trans. 
Amer. Electrochem. Soc, Vol. XX, 1911, pp. 105-19. 



119 



CHAPTER VII. 

USES OF GRAPHITE. 

The outstanding physical properties of graphite, namely its refrac- 
toriness, inertness, high electric and thermic conductivity and resistance 
to attack by chemical agents, render it of extreme importance in a variety 
of modern industries, while its lustre, complete opacity even in the thinnest 
flakes, softness and slipperiness, are additional properties that have 
extended its usefulness to several important branches of industry. 

In order of present importance, the principal uses of natural graphite 
are in the manufacture of crucibles, lubricants, pencils, foundry facing, 
paints, stove polish and dry batteries, while small amounts are also used 
in electrotyping and as a boiler scale preventive. According to a competent 
authority, the world's production of natural graphite is divided among 
the more important of the industries mentioned above, approximately as 
follows : — 

Crucibles . 75 per cent 

Lubricants 10 

Pencils 7 

Foundry facing and stove polish 5 

Paints . . 3 " 

It is obviously impossible to ascertain the proportions with strict 
accuracy, and the consumption of several of the minor industries will 
doubtless reduce the above percentages slightly, without, however, 
materially altering the ratio. 

In addition to natural graphite, there is a large production of artificial 
graphite, for which no allowance has been made in the above table. 
Artificial graphite is manufactured from anthracite coal or petroleum 
coke in the electric furnace, and is largely utilized for graphite electrodes, 
for which there is an ever-increasing demand. A quantity of this manu- 
factured graphite is consumed in the lubricant and paint industries, and 
it also enters into dry batteries and boiler scale preventives. 

CRUCIBLES. 

About 75 per cent of the world's output of graphite is estimated to be 
consumed in the manufacture of crucibles and such refractory accessories 
as stoppers, stirrers, nozzles, phosphorizers, etc., used in melting metals, 
such as steel, brass, and other non-ferrous alloys. 

The chief raw materials entering into the composition of a graphite 
crucible — namely, clay, graphite, and sand — need to be selected with 
great care as to their purity and suitability for the purpose. Even the 
most refractory fireclay will stand up for only a short time when in contact 
with molten metal, especially molten steel. If, however, graphite is added 
to the clay, the crucible will last as long as there is sufficient graphite left to 
enable it to carry the weight of metal and to stand handling. Aside from 
its refiactoriness and its function of preserving a crucible from corrosion, 
graphite is an extremely good conductor of heat, and a graphite crucible 
is thus able to stand sudden changes of temperature, while the charge 

67945—9 



120 

melts much more quickly than in a clay crucible. Although a good graphite 
crucible Tvill withstand sudden changes of temperature repeatedly, it is 
bad practice to subject a crucible to such treatment, and careful handling 
by pre-h eating and gradual cooling between melts will materially extend 
its life. The great expansion of the steel trade in recent yeais has led to 
the establishment of large crucible works in Europe and the United States; 
in addition to which, many of the large iron and steel works manufacture 
their own crucibles. 

In addition to the quality of the raw materials entering into crucibles, 
physical and mechanical considerations are important factors. The 
materials used should be mixed in a manner to impart to the finished 
article the proper density and solidity and at the same time give it a 
certain toughness, both in the unannealed state and when exposed to furnace 
conditions. Size of grain and their cohesive properties, as well as proper 
mixing, all materially affect the quality of the finished product. 

The superiority of a graphite over a clay crucible, due to higher heat 
conductivity, permits of a far larger charge in the case of the former. 
While a clay crucible in steel work is given a charge of only about 60 pounds, 
a graphite crucible is commonly given over 100 pounds. For the same 
reason, the number of charges taken from a steel furnace using graphite 
crucibles, in 24 hours, is as high as seven or eight, while with clay crucibles 
only about four charges are taken in the same time. 

The conductivity of a crucible varies directly with the percentage 
of graphite employed in the mixture, and the loss of heat in transmission 
through the crucible wall varies with the wall's thickness. If graphite 
possessed the necessary cohesive properties and strength, the ideal crucible 
would be one made entirely of graphite, but in actual practice, the higher 
the percentage of graphite used, the weaker is the crucible wall, and 
consequently the proper proportions of clay and graphite to be used have 
to be gauged to a nicety, according to the treatment to which the crucible 
is to be subjected. 

It is evident from the nature of the conditions that crucibles are 
required to stand up under, that the purity of the ingredients forming 
the crucible mixture, once a satisfactory formula has been obtained, is a 
matter of the greatest importance, and for satisfactory results, the strictest 
control is necessary. Particularly is this the case in the matter of the 
graphite used, and graphite containing more than an unavoidable minimum 
of such foreign minerals as mica, calcite, pyiites, quartz, etc., at once 
affects the life and strength of the crucible. Of the minerals mentioned 
quartz is probably the least injurious, as a certain proportion of quartz 
is added to the crucible mixture in any case. Mica fluxes readily and 
pin-holes the crucible wall, and is considered the worst impurity in a 
crucible grade of graphite. Being of similar size and shape to the graphite 
particles, mica flakes are extremely hard to eliminate from certain American 
and Canadian micaceous graphite ores, and the processes hitherto employed 
for cleaning the graphite have in many cases failed to make a sufficiently 
clean separation to satisfy the crucible trade. It is hoped that with the 
introduction of oil flotation this state of affairs may be remedied, and 
that, at the same time, a better recovery of the graphite in the ore may be 
effected. Calcite is objectionable, since it loses mass on heating, the 
carbon dioxide expelled forming blow-holes. 

Ceylon plumbago has always been considered pre-eminently suitable 
for crucible work, owing to its extreme purity and, in addition, its dense 



121 

character. The latter quality is considered of high importance, since on 
grinding, this graphite breaks up into more or less angular fragments of 
a wedge or rod-like shape; these possess material thickness and are com- 
monly considered to form a better bond with the clay used than do the 
thin, flat flake graphites, as well as to resist oxidation longer. On the 
other hand, some authorities claim that since one of the important func- 
tions of the graphite particles in a crucible wall is to take up expansion 
and contraction strains, a large number of thin, overlapping flakes is 
preferable to a smaller number of more or less angular fragments. The 
thin flakes would permit of a certain amount of slipping movement amongst 
themselves during expansion and contraction, being in more or less parallel 
arrangement, and would counteract the tendency of the wall to crack. 
As a matter of fact, there is a considerable divergence of opinion on these 
points, and there would appear to be a lack of actual evidence as to which 
of the views held is in accordance with the facts. At the present time, the 
matter of the suitability of flake graphite for crucibles is being investigated 
by the United States Bureau of Standards, in conjunction with a similar 
investigation of American clays for the same purpose. It is to be hoped 
that this research work may throw some light on what has been rather a 
vexed question, and that the tests, conducted under actual working condi- 
tions, and under government supervision, of crucibles made with the 
different grades of graphite, may definitely decide as to their respective 
merits or demerits. The importance of the above question is evidenced 
by the fact that the United States Government early in 1918 decided to 
declare a partial embargo on graphite imports and to limit the quantity that 
might be brought into the country from overseas during the current year 
to 5,000 tons 1 . This action was taken in order to conserve ocean tonnage and 
to encourage domestic production of graphite. In Alabama alone, early 
in 1918, something like forty companies were operating or about to oper- 
ate; and as the object was to produce a crucible grade of graphite, pro- 
ducers demanded some measure of protection from the competition of 
Ceylon plumbago, Should it be shown satisfactorily that flake graphite 
can be used to replace Geylon plumbago in crucibles, the Alabama field 
would be in a position to supply a large part of the graphite required by 
American crucible manufacturers, while Canadian graphite will also doubt- 
less continue in considerable request for the same purpose. In this con- 
nexion, it may be noted that previous to the removal of all restrictions on 
January 16, 1919, the United States Government, as a war measure, 
required crucible makers to add 20 per cent of American flake graphite 
to their crucible stock. 

In the above connexion, it may be noted that there was a considerable 
falling off in the demand for graphite crucibles for steel work during 1917-18, 
due to the increasing number of electric furnaces making tool steel. These 
furnaces take a charge of from four to ten tons as compared with 60 to 75 
pounds for a crucible, and their adoption has been attributed largely to 
the difficulty of obtaining satisfactory graphite crucibles and their high 
price. The cutting off of the supply of Klingenberg clay, which was 
considered essential to satisfactory crucibles, and the rise in price from 
10 cents per pound in 1914 to 30 cents per pound in 1917 for Ceylon plum- 
bago, laid down at New York, caused American crucible makers to experi- 

1 Under War Trade Board ruling No. 157, made in July, 1918, the above embargo was made 
absolute for the remainder of the year, rail borne shipments from Canada and Mexico excepted. 
(Embargo lifted January 16, 1919. ) 

67945—9§ 



122 

ment with domestic clays, at the same time using varying amounts of flake 
graphite mixed in with the Ceylon plumbago. These experiments may be 
said to be still proceeding, although manufacturers claim to have already 
found satisfactory substitutes for the German clay and to be making pots 
of equal quality to those made with the imported article. While this may 
be partially true, as regards brass crucibles, the new steel pots do not appear 
to have the same life as those formerly made. Even with the high price 
of electrical power at many steel making centres, the use of electric furnaces 
for making tool steel would appear to effect considerable economy over 
that of graphite crucibles, and it seems probable that their adoption will 
become even more general, resulting in a corresponding decline in the 
demand for graphite crucibles for this class of work. In February, 1918, 
several of the larger American crucible works reported a decided falling 
off in orders, and were working at about only 60 per cent capacity, most 
of the demand being for brass pots. 

While Ceylon graphite is claimed to be the best procurable for crucible 
work, manufacturers have long made a practice of mixing in a small amount 
— 15 to 25 per cent — of flake graphite. This material is considerably 
cheaper than the Ceylon mineral, and its use in amounts not exceeding 
the percentage quoted is claimed not to affect the quality of the crucible. 
The flake graphite used comes from various sources, domestic mines, 
Canada, and in recent years, in increasing quantities, from Madagascar. 
The latter graphite has the merit of being produced much more cheaply 
than American flake. 

The size of the graphite particles used in crucible mixtures is commonly 
20-90 mesh, these being the limits stipulated for by makers. As both the 
Ceylon and flake graphites are usually re-treated by the manufacturer 
by a grinding and screening process, a certain amount of fine dust* is pro- 
duced., This dust is not used in crucibles but can be employed in lubri- 
cants, paints, etc. Graphite for the latter purposes brings a considerably 
lower price than what is known as crucible flake, and it is therefore to the 
crucible maker's advantage to obtain as large a flake as possible in order 
to reduce the amount of dust produced on grinding. This grinding is 
commonly performed between burrstones. Any gritty impurities that 
there may be in the graphite are eliminated by this process, being reduced 
to powder and falling off with the fine dust graphite on screening. While 
the milling process that the flake graphites have to undergo removes the 
majority of these impurities, the flake in its natural form being of the size 
and form required, Ceylon graphite is imported in the form of "lump" or 
"chip", having undergone only a rough hand sorting and screening before 
shipment. This treatment, known as curing, suffices to remove most of 
the mineral impurities present; the graphite occurring in a massive form 
and being relatively clean in the natural state. 

The degree of purity demanded for crucible flake graphite is not less 
than 90 per cent carbon, but mica is always regarded as highly objection- 
able and a 90 per cent carbon material in which the remaining 10 per cent 
is all mica would not be considered suitable. As a rule, however, the 
impurities include mica, quartz, calcite, pyrites, feldspar, etc., and it has 
proved impracticable hitherto in ordinary milling practice to secure a 
product carrying much under 10 per cent of these substances. In the case 
of Canadian flake graphites, mica, quartz and pyrites are often extremely 
intimately intergrown with the graphite. The quartz and pyrites are 
largely present in a state of extremely fine division between the graphite 



123 

laminae, and it is almost impossible, to remove them entirely without 
destro3 r ing the flake; the mica is largely interleaved with the graphite 
flakes. 

It is considered essential that crucible graphite possess a scaly or 
lamellar structure, as this type of graphite enables a pot to stand up in 
the furnace far more effectively than does earthy or amorphous graphite. 
This, as explained above, is considered due to the fact that a certain amount 
of slipping takes place between the graphite particles during contraction 
and expansion of the crucible and that this prevents cracking. Very finely 
divided graphite, also, burns more readily than larger particles. 

As regards the relative refractoriness of graphite for crucibles, the 
variation exhibited by the flake and Ceylon graphites appears to be compar- 
atively slight. Hoffmann made some experiments along these lines upon 
Ceylon, Ticonderoga and Canadian graphites, and the results showed 1 
a practically negligible difference between the various samples in the amount 
of carbon burnt off in a given time. 

A. V. Bleininger has pointed out in a recent article that the question 
of the utilization of Ceylon or flake graphite in crucibles is one of the relative 
crucible value of the two materials per dollar, and does not imply that flake 
graphite cannot be used for the purpose. From a dollar's worth of Ceylon 
graphite, however, greater crucible value is obtained than from a dollar's 
worth of flake, as a better crucible can be made from it. This is well 
shown in the following extract 2 : — 

It is a difficult matter to replace Ceylon graphite altogether with the domestic 
mineral. In the first place the greater density of the imported material, 2-25, which 
imparts to it the characteristic resistance to oxidation, its foliated structure, and the low 
ash content of the best grades combine to make it extremely satisfactory for the purpose 
of crucible making. This graphite can be bonded together with a comparatively small 
amount of clay, since the surface factor per unit weight is smaller than for that of any 
other kind of graphite. 

This point may be illustrated by the volumes occupied by the same weight of several 
types of graphite. Thus, 100 grams of ground Ceylon graphite after thorough shaking 
occupies a volume of 90-7 c.c, Canadian graphite 119-6 c.c, and Alabama graphite 
152-0 c.c. In other words, it would be impossible to make graphite mixtures of maximum 
carbon content from the two American materials. Since they offer a much larger surface 
the amount of clay used must be greater. From this it follows that the ultimate density 
and thermal conductivity are certain to be lower. 

To what extent American flake graphite can be admixed with the Ceylon graphite 
remains to be seen. The writer has seen mixtures in which the flake added amounted 
to 20 per cent of the total graphite content and gave fair foundry results. It might be 
possible, however, to perfect processes which will enable the crucible maker to employ 
larger percentages of domestic graphite, and at the same time secure practically the same 
results as with Ceylon graphite. On the other hand, there is no reason why a large 
quantity of domestic graphite should not be used in the making of stoppers and similar 
articles. The comparison made between the Ceylon and flake graphite is, of course, 
relative, and refers to crucible value obtained per dollar at the present time. If for some 
reason this country could no longer obtain Ceylon graphite, the production of metal 
certainly would not be diminished in any way, as we could get along very well with flake 
and amorphous graphite, furnace carbon and coke. 

The United States Bureau of Mines has lately conducted experiments 
designed to determine the fusibility of the ash yielded by graphites from 
various sources, and its influence on the refractoriness of the bond clays 
used in crucible making. The results of these experiments showed 3 that, 
while the ash of different graphites varies widely in relative fusibility, the 
softening point cannot be taken as a true criterion of the behaviour of the 

1 Geol. Surv. Can., Rep. Prog., 1876-7, p. 489. 

2 Canadian Chemical Journal, October, 1918, page 253. 

3 Journal of the American Ceramic Society, Vol. II, No. 1, Jan. 1919, p. 68. 



124 

ash in a crucible body. Also, that the tendency of graphite ash to lower 
the refractoriness of a crucible is not evident at brass-melting tempera- 
tures and would seldom be detrimental even in steel-melting crucibles. 
It was also shown that the ash of Alabama graphite exerts a lesser degree 
of fluxing action than that of Ceylon, Canadian, Pennsylvania, and New 
York graphites. 

In the course of the experiments conducted by the above Bureau in 
the manufacture of crucibles from graphites from various sources, the 
following figures of chemical and screen analyses were secured on samples 
of graphite obtained from American producers 1 . 

Results of Chemical and Screen Analyses of American Graphites. 



Description. 


Percentage of 
Carbon. 


Cumulative percentages. 


Volatile. 


Graphitic. 


On 
20-mesh. 


On 
35-mesh. 


On 
65-mesh. 


On 
100-mesh. 


Through 
100-mesh. 




1-27 
1-68 
1-32 
3-65 


87-82 
82-02 
92-09 
74-67 


0-3 


11-7 

0-1 
2-5 
3-3 

15-4 
5-7 
6-7 
9-7 

8-2 


54-9 
420 
28-0 
30-3 
69-6 
58-5 
56-4 
62-2 
69-6 


95-9 
94-8 
60-0 
89-6 
95-6 
930 
97-0 
92-4 
99-7 
10-5 
67-6 
22-2 
3-2 
0-2 
3-9 


4-1 


No. 1 flake . . 


5-2 


a 




40-0 


u 




10-4 


« 


0-1 


4-4 


a 






7-0 


« 


1-98 


86-18 


0-1 


30 


M 


7-6 


« 


1-08 
2-96 
2-31 
2-17 
6-06 
7-37 
7-20 


92-43 
80-44 
81-43 
86-30 
41-33 
32-41 
31-47 




0-3 


No. 2 flake 




89-5 






0-2 
0-1 
0-1 


9-9 
0-3 

1-2 


32-4 


" 




77-8 


Dust 




96-8 


<« 




99-8 


« 






0-4 


96-1 











The screen analyses were made with Tyler Standard Ro-tap apparatus, 
the samples being screened for 45 minutes. In connexion with the carbon 
determinations, a tentative standard was adopted for what is here termed 
volatile carbon; by this is meant the carbon burnt off during a preliminary 
ignition lasting 3 minutes, at a temperature of 800°C. The table shows 
that the amount of such volatile carbon was found to be greatest in the 
dust samples, practically all of which passes a 100-mesh screen; and it 
therefore appears probable that a proportion at least of such loss repre- 
sents graphitic carbon, which burns off more rapidly in the case of finely 
divided material than of that consisting of large sized particles. 

The figures quoted illustrate the wide variation both in the carbon 
content and size of flake of the various grades of commercial graphite as 
supplied by different producers. 

In the following table 2 is shown the complete chemical composition 
of seven samples of graphite as prepared for crucible work: — 

1 Dub, G. D., op. cit., p. 20. 
2 Dub, G. D., op. cit., p. 21. 



125 



Composition of Seven Samples of Crucible Graphite. 





Alabama. 


Alabama. 


Alabama. 


Alabama. 


New York 


Penn- 
sylvania. 


Ceylon. 




Volatile carbon 

Graphitic carbon 


2-08 
84-52 
7-02 
5-06 
0-53 
0-14 


1-40 
90-58 
3-99 
2-96 
0-18 
0-19 


2-66 
81-82 
8-33 
6-35 
0-39 
0-13 


1-31 
91-18 
4-08 
2-31 
0-40 
0-13 


1-30 
88-97 
4-34 
2-40 
1-08 
0-38 
0-07 
0-76 
0-55 
0-12 


1-53 
88-80 
5-24 
2-05 
1-75 
005 


1-68 

85-06 

7-81 




..2-82 




1-61 




0-13 




0-19 




0-23 
015 
001 


0-16 
0-23 
001 


0-06 
0-14 
0-11 


0-08 
0-31 
0-03 


0-09 
0-08 
012 


0-21 




0-25 




011 








99-74 


99-70 


99-99 


99-83 


99-97 


99-71 


99-87 



These figures show that, from the point of chemical composition, flake 
graphites, properly refined, compare well with Ceylon plumbago. 

A most interesting and instructive paper on the " Structure of Graphite 
in Relationship to Crucible Making," recently appeared in the Journal 
of the American Ceramic Society, (July, 1919, pp. 508-542.) The author, 
R. Thiessen, of the United States Bureau of Mines, has conducted an 
exhaustive investigation of the structure of graphite from Alabama, 
Pennsylvania, Canada, Madagascar, and Ceylon, and of the effect of burn- 
ing on the crucibles made with them. The investigation consisted in (1) 
a microscopical examination of the various graphites to determine both 
the predominant size and shape of particles and, at a very high magnifica- 
tion, the inner structure of such particles; (2) a similar examination of 
cross-sections of crucible walls made with different graphites, both before 
and after burning. It was found that the graphite of a crucible made 
with flake graphite whose flakes were uniformly small rather than uniformly 
large, were evenly and closely packed and were arranged parallel to one 
another and to the crucible wall, resisted oxidation longest, and such 
a crucible, therefore, might be expected to give the best foundry service. 

This is in direct contradiction to the opinion held by many crucible 
makers that Ceylon plumbago, by reason of its greater density, is superior 
for crucibles to flake graphite. The paper contains a number of micro- 
photographs that illustrate admirably the structure of the graphites 
examined and also the effect of burning on the crucibles made with different 
graphites, and is an important contribution to our knowledge of what 
has long been a very vexed question. 

Clays for Crucibles. 

In view of the importance of the quality of the clays employed in 
crucibles, it may be pertinent to include here some remarks as to the 
requirements of the crucible trade in this connexion. 

Although fireclays are of widespread occurrence, relatively few such 
clays have proved suitable for crucible manufacture. Probably the best 
clays for this purpose so far found are the Stourbridge (English) clay, and 
the Passau and Klingenberg clays, of Bavaria. The Klingenberg clay, 
especially, on account of its high purity, homogenity and refractoriness, 
was employed almost exclusively in pre-war days for crucible work, not 



126 

only in Europe but also in the United States. The cutting off of 
the supply has forced crucible manufacturers to experiment with other 
clays, and in the United States substitutes have been found in mixtures 
of clays from different localities. The Bureau of Standards, United 
States Department of Commerce, has made a laboratory study of the sub- 
ject 1 ; and, as a result, it is suggested that, although there seems to be no 
reason to think that such clays cannot be found in the United States, it 
is believed the best solution of the problem would probably be to depend 
on a mixture of two or more clays representing both those of the open and 
more refractory and those of the dense and vitrifying variety, such as the 
well known clays of the St. Louis region and the ball clays of Tennessee 
and Kentucky, or the plastic fireclays of Ohio and Pennsylvania 2 . It has 
proved, however, apparently not a simple matter to produce in practice, 
from a mixture of clays, a product in every way the equal of a high grade 
fireclay, such as the Klingenberg variety; and crucible makers, basing 
their statements on the reports of their customers, are by no means agreed 
that a satisfactory substitute for the imported crucible clays has yet been 
produced from a blend of domestic clays 3 . It is manifestly difficult to 
secure satisfactory data as to the relative quality of the pots made from 
these experimental mixtures, since the life and general behaviour of a 
crucible are largely dependent on the treatment and handling it receives, 
and these necessarily vary considerably in different plants. The experi- 
ments that the Bureau of Standards now have under consideration, that is, 
the manufacture on a commercial scale of crucibles from mixtures of differ- 
ent domestic clays, followed by a testing of the pots under actual working 
conditions and under government supervision, should provide much needed 
and reliable data on this head. 

The following excerpts from Technologic Paper No. 79, of the Bureau 
of Standards, serve to illustrate some of the more important points in 
connexion with the choice of clays for crucible purposes. 

The requirements of such clays are very exacting and may be summarized as 
follows: First, they must possess sufficient refractoriness to withstand the high heat 
of the furnaces, under the pressure of the liquid charge, without showing deformation; 
second, great plasticity and bonding power, making possible the cementing together 
of the grains of calcined material to a satisfactory compact mass; third, considerable 
mechanical strength and toughness, especially in the dried state; fourth, the 
quality of becoming dense at comparatively low temperatures, in order to produce a 
structure impervious to the liquid metal and resisting its corroding influence; fifth, the 
property of retaining a sound structure, free from vesicular development upon long con- 
tinued heating; sixth, the quality of resisting sudden temperature changes without 
checking or spalling; seventh, the property of drying and firing safely without cracking. 
These requirements are severe and are possessed by comparatively few clays. 

The chemical, and with it the mineral, composition of the plastic fireclays is 
obviously of fundamental importance; but it is influenced and modified so largely by 
physical conditions that as a guide in the selection of suitable clays it is of secondary 
service. This is illustrated by the fact that we have in the United States a large number 
of clays practically identical or closely approaching the chemical composition of the best 
known European bond clays but which fail completely in satisfying the requirements. 
We are compelled, therefore, to assign to chemical composition a secondary value. This 
does not mean, of course, that the composition is to be entirely neglected. It must always 
correspond to that of refractory clays. Any excess of fluxes would evidently render the 
material valueless, since refractoriness is one of the conditions to be met. The fact to be 



1 Bleininger and Schurecht, Properties of Some European Plastic Claj^s, Tech. Paper No. 79, 
U. S. Bur. Standards, 1916. 

2 Mineral Resources of the United States, 1916, Part II, p. 560. 

3 See M. McNaughton, The Crucible Situation, Trans. Amer. Inst. Metals, Vols. XI-XII, 
1917-8, p. 208. 



127 

realized is that it fails to differentiate between the several types of fireclays, all of which 
are sufficiently refractory for the purpose. 

The strong plastic clays of the type under discussion show considerable contraction 
in volume upon drying. At the same time, there is a distinct tendency on the part of 
some clays, such as the well known Klingenberg material, to air check. Both of these 
items deserve attention. The difficulty due to air cracking is, of course, largely overcome 
in actual use by the employment of a large proportion of non-plastic material in the form 
of calcined clay, crushed potsherds (grog) and graphite. The volume shrinkage is a 
function of the rate of drying, which is governed by the temperature (humidity) and the 
velocity of flow of the air around the piece being dried. As a rule the shrinkage is found 
to be smaller when the drying proceeds rapidly and larger when the process is taking place 
more slowly. 

Plastic fireclays may be roughly divided into two classes, namely, open, and dense 
burning materials. The former, when fired to high kiln temperatures, say corresponding 
to pyrometric cone 14 to 16 (1410° to 1450°C.) retain their open structure, owing to the 
small amounts of fluxes, iron oxide, lime, magnesia, and the alkalies. The second type 
burns to a dense mass at these temperatures or below and may even show overburning 
or the formation of a vesicular, spongelike structure. Both types of clay are necessary. 
The first type is inherently more refractory and is able to withstand load conditions at 
furnace temperatures more satisfactorily. The second type is useful in closing up the 
pores of the material and producing a dense mass resistant to the corrosive action of slags. 
The ideal condition would be obtained by the use of a mixture of the two classes of clays 
and restricting the amount of the dense-burning material to the minimum necessary 
to bring about the desired density. The study of the rate of condensation or vitrifica- 
tion is usually followed by determining the decreasing absorption of water, or 

porosity, at a series of increasing temperatures. Decreasing porosity must, in the nature 
of the case, parallel the process of vitrification. The higher the content of fluxes the larger 
must be the quantity of the matter softening under the influence of the heat, so that 
condensation or minimum porosity is reached at a comparatively low temperature. The 
open-burning clays, on the other hand, show no striking drop in porosity and retain their 
porous structure at the temperatures involved. This behaviour undoubtedly is due 
to their more refractory character, viz., the low content of fluxes. The term over burning 
is used to indicate the formation of vesicular structure, due to the evolution of gases. 
This is evidenced by the fact that during this stage the porosity again increases, since 
the clay becomes more or less spongelike in character. The usefulness of the clay is 
seriously lowered even during the incipient formation of this structure, as it is evidence 
that the clay has softened to a very great extent, and owing to the resumption of the 
greater porosity, becomes more subject to the action of corroding slags. Fortunately, 
in the presence of fine and coarse grained calcined clay of high refractoriness (grog), the 
formation of the vesicular structure is opposed by allowing the gases to escape more readily, 
by the solution of the fine grained refractory clay, with consequent stiffening, and by the 
mechanical effect of the skeleton of coarser grog particles. This condition is subject 
to regulation by the sizing of the grog, which makes necessary both the introduction of very 
fine particles and a series of coarser sizes. The adjustment of the sizes should be such 
that maximum density is produced in the dried state. It is specially important to keep 
in mind the function of the fine grog, a fact not as commonly realized as it should be. 

A plastic fireclay which shows some formation of vesicular structure need, therefore, 
not be condemned on this evidence alone. If, however, it persists in bloating when 
admixed with grog, its use becomes decidedly questionable. 

Clays do not possess a definite melting point like minerals and metals, and softening 
takes place during a long temperature interval. In this connexion it is important to note, 
in determining the so-called fusion or melting point of clays by means of pyrometric cones, 
that time is an important factor, which is illustrated by the fact that this arbitrary degree 
of softening occurs at a lower temperature when the heating is continued for a longer time 
and vice versa. 

The ultimate softening temperature is apt to be a misleading criterion as regards 
the practical usefulness of a refractory. Thus, based upon the Seger kaolin-silica fusion 
curve, siliceous clays are considered of an inferior grade compared with the high-clay 
materials. As a matter of fact, clays high in silica and low in fluxes may show excellent 
refractory qualities in practical use and may stand up under severe conditions. The fact 
that the siliceous clays may fuse at a lower temperature is not of much practical significance. 
Such materials possess the important advantage^of not softening throughout a considerable 
temperature range, as is the case with the clays approaching the composition of the pure 
clay substance, and usually stand up at heats close to their ultimate softening point. 

Klingenberg clay, from Bavaria, is especially favoured for the manufacture of 
graphite crucibles, and up to the present time has been used exclusively for this purpose 



128 

by American makers. The best selection mentioned in the literature is said to approach 

closely the following composition : — 

Per cent 

Silica 54-06 

Alumina 33-11 

Ferric oxide 1-50 

Lime. 0-49 

Magnesia 0-45 

Potash and soda 1-37 

Loss on ignition 9-12 

This clay is one of the most plastic clays known. It appears to be quite high in 
organic matter. Unmixed with non-plastic matter it has a decided tendency to check 
and crack on drying. There are several grades of this clay on the market which differ 
in refractoriness. 

For the purpose of comparison with clays under trial for crucible work, the following 
data obtained by tests on Klingenberg clay are quoted: — ■ 

Minimum water content with which clay can be worked — 

Per cent water 17-95 

Per cent linear drying shrinkage 2-02 

Water content between minimum and normal — 

Per cent water 31-00 

Per cent linear drying shrinkage 3-06 

Normal consistency — 

Per cent water 40-12 

Per cent linear drying shrinkage 9-41 

Water content between maximum and normal — 

Per cent water 52-25 

Per cent linear drying shrinkage 18-33 

Maximum water content with which clay can be worked — • 

Per cent water 66-20 

Per cent linear drying shrinkage 24-92 

Difference between maximum and minimum water content 48-25 

Difference between maximum and minimum shrinkage 22-90 

Fineness = amount of clay removed by water current of 0-18 mm. per second, 

per cent by weight 54-6 

Tensile strength in plastic state, pounds per square inch 4-05 

Time of disintegration of dried clay in water, minutes 120 

Tensile strength of dried clay, pounds per square inch 62-9 

Modulus of rupture of dried clay, pounds per square inch : 301-0 

Tensile strength of dried clay with 50 per cent grog, pounds per square inch .... 177 • 5 

Modulus of rupture of dried clay with 50 per cent grog, pounds per square inch.. 538-0 

Drying factor 75-3 

Drying behaviour of clay ! Cracks. 

From a test of five European plastic fireclays, the most suitable for graphite crucibles 
were found to be the above Klingenberg clay and a plastic pot clay from St. Loupe, in 
France. It is suggested that the Klingenberg clay might be improved for the above 
purpose by an admixture of an easy drying clay having low shrinkage, such as the glass 
pot clay from Gross Almerode, Germany. 

Klingenberg clay has a low vitrification temperature, reaching a state of advanced 
density at 1125°C and retaining this condition up to 1350°C, when it begins to become 
porous owing to the formation of a vesicular structure, due to overheating. The low 
vitrification temperature is an important property in graphite crucibles for brass melting, 
but is not of such value in steel work. For the latter purpose, the French St. Loupe clay 
would seem to be better adapted, showing a more gradual vitrification and retaining 
a lower density than Klingenberg: clay up to, and evidently beyond, 1375°C. 

For crucibles used at lower temperatures, Klingenberg clay is undoubtedly highly 
superior, since it becomes dense at low temperatures and thus protects the graphite 
from oxidation. A slower vitrifying clay may be of advantage in some cases where 
temperatures above 1250° are involved, but at lower temperatures it tends to leave the 
structure open too long and hence causes' oxidation of the carbon. The low vitrification 
temperatures of Klingenberg clay is due to the high content of total fluxes. 

Summarizing, it is shown that the bond clay serving best for graphite crucibles 
to be used in brass melting evidently is one which becomes dense at a comparatively low 
temperature, thus excluding the oxygen of the air from the carbon grains by enveloping 



129 

them with a protective layer of clay. Klingenberg clay stands pre-eminent for this purpose 
up to temperatures of 1350°C and somewhat higher, the admixture of graphite apparently 
tending to increase the refractoriness of the mass. For melting steel, the French St. Loupe 
clay is probably slightly to be preferred, owing to its somewhat higher density at 
temperatures between 1250°C and 1375°C, which enables it to resist corrosion by slag 
to a greater degree. 

Regarding the possibility of finding satisfactory substitutes amongst 
domestic clays for the foreign crucible clays the authors conclude : — 

Some of the users of such materials have sought to replace these clays by 
individual American clays. There is no reason to believe that such clays can 
not be found in the United States; in fact, materials have been tested in this laboratory 
which approach the foreign clays in quality. It would be far better, however, to 
depend upon a mixture of two or more clays, representing both clays of the 
open and more refractory, and of the dense and vitrifying variety to secure the 
desired condition. Among clays of the latter type are listed the ball clays or semiball 
clays of Tennessee and Kentucky, and some of the plastic No. 2 fireclays of Pennsylvania 
and Ohio. It is important to realize that an open-burning clay of the Gross Aim erode 
type, whether it be like the plastic clays from Missouri or New Jersey or the siliceous clays 
from Arkansas, should be blended with one or more clays of the opposite type and not 
with materials of the same class, a mistake which is sometimes made. Likewise it should 
be realized that a bond clay suitable for glass work is not necessarily adapted for use in 
graphite crucibles, where greater density of structure at lower temperatures is essential, 

By adjusting the proportions of the two kinds of clay, and by thorough 

mechanical blending through fine grinding, the desired quality can be obtained as well as 
maintained with results which should be superior to those which have been had with the 
single imported clays. The claim that no American clays are available which answer 
the purposes of the industries involved is fallacious, a fact supported by actual foundry 
results communicated to the writers. Open-burning plastic clays of good refractoriness 
are found in Alabama, Colorado, Georgia, Arkansas, Illinois (southern part), Kentucky, 
Missouri, New Jersey, Ohio (southern part), and Tennessee. In the same States, and 
frequently close to other deposits, dense-burning clays are also found, to which must be 
added materials of this class found in Maryland. There is no lack of materials, and it is 
a question only of selection. 

Based on the results of the tests conducted on a series of high grade 
European plastic fireclays, the writers suggest the following tentative 
specifications as being of service in selecting plastic bond clays for 
crucibles: — 

Plastic bond clays should possess a considerable water shrinkage range, one of 
about 40 per cent between the minimum and the maximum water contents, permitting 
of molding of the clay. In the case of siliceous clays, allowance should be made 
for the content of nonplastic constituents and the permissible range reduced to 
20 per cent, provided the materials fulfill all other essential requirements. The 
Atterberg plasticity number should not be lower than 50 nor higher than 110. The 
ratio of the percentage of the shrinkage to the per cent of pore water should not be greater 
than 1:1-2. The total water content, for normal consistency, expressed in terms of the 
dry weight, should be between 30 and 45 per cent. When intimately mixed with 50 per 
cent of potters flint (by weight) the time of complete disintegration in water of a seven- 
eighth inch cube in the dried state, made of the mixture, should not be less than 50 minutes, 
the water being at room temperature. The tensile strength of the clay in the plastic 
state should be close to 4 pounds per square inch. The linear drying shrinkage should not 
be less than 6-5 and more than 10 per cent of the dry length, the drying to be done at room 
temperature. 

When made up with 50 per cent, by weight, of hard burned grog, which passes 
the 20-mesh sieve and shows residues of 34 per cent on the 40 mesh, 27 per cent between 
40 and 100 mesh, 12 per cent between 100 and 150 mesh, and of which 27 per cent passes 
through 150 mesh, suitable dried test specimens should show the following minimum 
strengths: Tensile strength, 150 pounds per square inch; modulus of rupture, 350 pounds 
per square inch. The drying should be so conducted that the specimens are kept at room 
temperature until shrinkage has ceased, when they are to be heated to 75 and 110°C, 
respectively, and to constant weight in each case. 

Dried specimens of the clay should be fired in a suitable kiln at a rate corresponding 
to a. temperature increase of approximately 20°C per hour, beginning at 1000°C and 
withdrawn from the kiln at intervals of 20° or 25°C. Absorption and porosity determina- 
tions should be made upon all pieces. The clays should show a porosity of not more than 



130 

10 per cent at 1150°C, at 1250° approximately 5 per cent, and should then maintain 
practically constant porosity up to 1350° in the case of materials intended for graphite 
crucibles used in brass melting and 1400° for crucibles employed for steel. The linear 
burning shrinkage may vary, for the unmixed clay, from 5 to 8 per cent, in terms of the 
dry length, and should not exceed the higher limit. The softening temperature of the 
plastic clays should not be below that corresponding to cone No. 30. 

The percentage content of total fluxes, Fe 2 3 , CaO, MgO, K 2 0, and Na 2 may 
approach 5 per cent. 

Dr. Bischoff, a German authority on clays, conducted a special inves- 
tigation of Klingenberg clay, the results being published in a separate 
paper in 1903. The tests were conducted on both the No. 1 and the No. 2 
grades, which are stamped before shipment with a coat of arms and the 
letters K. B. 2 respectively. 

The tests included: — 

(1) Comparison of physical qualities; 

(2) Elutriation test for fineness of grain; 

(3) Pyrometric determinations; 

(4) Chemical analysis. 

Chemical analysis showed: — 

No. 1. No. 2. 

Alumina 31-16 30-43 

Silica. 54-16* 55-76** 

Magnesia. 0-38 0-27 

Lime 0-40 0-34 

Ferric oxide 1-66 1-37 

Potash 0-97 0-72 

Iron pyrites trace trace 

Loss on ignition 11-48 11-42 



100-21 100-31 

Calculated as free from water and carbon the above results show: — 

No. 1 No. 2 

Alumina... 35-18 34-36 

Silica 61-15 62-95 

It is concluded from the tests made that the No. 1 clay is more suitable 
for crucibles than the No. 2, important considerations being that the former 
has a considerably higher content of finely divided clay material and that 
it acquires greater volume when mixed with water. Both of these facts 
make it extremely suitable for use in crucible bodies, as the graphite is 
thus more completely enclosed and incorporated in the clay mass and is 
better protected from oxidation. 

With regard to the occurrence in Canada of clays suitable for crucibles, 
the following statement has been furnished by the Ceramic Division of the 
Mines Branch: — 

Fireclays which may be suitable for use in the manufacture of crucibles are found at 
the following localities in Canada. None of these clays appear to have the precise qualities 
of the English and German crucible clays, but two or more varieties could be assembled 
in order to arrive at the proper requirements. 

* 31-11 chemically combined; 23-05 sand containing 22-91 silica and 0-10 alumina. 
** 33-81 chemically combined; 21-95 sand containing 21-80 silica, 0-12 alumina. 



131 

Nova Scotia. 

Shubenacadie. — Grey plastic fireclay occurs here. It burns to a fairly dense body 
and the shrinkages are low, i.e. the total shrinkage when burned to cone 9 is 10 per cent. 
This clay softens at cone 30. 

Middle Musquodoboit. — A series of beds of pink, red, white and mottled clays 
occur at this locality. 

These clays are very fine-grained and plastic. They burn to an impervious body 
at cone 6 to 9, depending on the quantity of red clays present, with a total shrinkage 
of 15 per cent. The softening points are from cone 20 to cone 27. 

A small quantity of these clays might be used in a crucible body, but not more 
than 15 per cent or so. 

Inverness, Cape Breton. — The most important deposit in this district is the clay 
overlying the 13 foot or Hussey coal seam. It outcrops on Big river and on McClellan 
brook. It is a very smooth, plastic, and rather sticky clay when wet. It burns to an 
impervious body at cone 5, with a total shrinkage of 17 per cent, and it softens at cone 25. 

On account of its good bonding and dense-burning properties this would be a useful 
clay to mix with more refractory open-burning materials for a crucible body. 

Coxheath, Cape Breton. — A deposit of felsite having a composition somewhat 
resembling that of a siliceous fireclay occurs at this locality. It is hard and non-plastic 
when ground and wetted, and resembles in this respect the flint clays in the United States. 
This material could be ground and screened to suitable size of grain to furnish the grog 
or coarse material in a crucible body. 

Quebec. 

St. Remi d'Amherst. — Kaolin or china clay occurs at this locality in workable 
quantities. The white kaolin is very refractory but there is some discoloured material 
also present which is not quite so refractory. These materials do not burn to a dense 
body at the ordinary temperatures at which refractory goods are made, so that they 
would require to be mixed with a dense-burning clay of lower refractoriness. This is the 
only body of refractory clay at present known in Quebec. 

Ontario. 

Refractory clays are not known to occur in the southern part of the province of 
Ontario. In the northern portion, however, there are deposits of high grade clays which 
would be suitable for crucible manufacture, but unfortunately they are situated beyond 
the reach of transport at present. 

Saskatchewan. 

Fireclays occur abundantly in the southern part of the province of Saskatchewan, 
in the vicinity of Claybank, Willows, Yellowgrass and other points. 1 These clays are very 
plastic and somewhat sticky, so that they would require the addition of some non-plastic 
ingredient to reduce their shrinkages. As natural, non-plastic, refractory material appears 
to be absent in this region it would be necessary to calcine a portion of the raw clay to 
furnish the grog. 

Reference has been frequently made in the preceding pages to the use 
of grog in crucible bodies. The term grog is used to denote material 
consisting of used crucibles that have stood a maximum number of heats 
or have broken in handling. These discarded pots are returned to the 
crucible works and are broken up, crushed and incorporated in the body 
of fresh crucibles. A usual proportion of grog in a brass pot is 10 per cent, 
but in steel pots its place is generally taken by silica sand. 

Manufacture of Crucibles. 

The materials for the manufacture of crucibles, while differing in some 
minor details, are practically the same everywhere. The preparation 
of the mixture, and the proportions of the various ingredients — graphite, 

A 

1 Clay Resources of Southern Saskatchewan, by N. B. Davis, Mines Branch, Ottawa, 1918. 



132 

clay, and grog or sand — entering into it, are generally the rather jealously 
guarded property of the individual makers, and this is more especially 
the case at the present time when so much experimental work with various 
clay and graphite mixtures is being carried on. 

The following are approximate mixtures for brass and steel pots : — 

Brass crucibles. Steel crucibles. 

Graphite 45 per cent 50 per cent. 

Clay 35 " 30 

Grog 10 " Sand 10 

Kaolin 10 " 10 

In exceptional cases, where very high refractory qualities are demanded, 
the proportion of graphite used may reach as high as 80 per cent, and over, 
but this amount is exceptional and results in a weak crucible. According 
to Ledebur, 1 crucibles for the manufacture of tool steel in Austrian steel 
works contain only 33-60 per cent of graphite, but the graphite used is 
the best grade of Ceylon, specially cleaned for the purpose. 

The clay is first kiln dried at a temperature of 120°C, until all moisture 
is driven off. It is then ground in small stamp mills, or, more generally, 
by edge-runners (chasers), and is then screened to remove lumps and any 
foreign matter. 

The graphite, whether it be Ceylon or flake, undergoes a certain amount 
of preparation at the crucible works, over and above what it has received 
previous to shipment. The standard grades of Ceylon crucible graphite 
comprise the following: — 

Lump No. 1 
Lump No. 2 
Chip No. 1 
Chip No. 2 
Dust 

The above grades vary considerably in their carbon content, ranging 
from as high as 92 per cent in the case of lump No. 1 to 70-75 per cent for 
dust, and the price of the different grades varies accordingly.' 

The lump and chip grades undergo a grinding and screening process 
at the works, the graphite used in the crucible mixture consisting of a 
mixture of various sizes of grain, in the proportions decided upon by the 
individual manufacturer as giving the best results. The very fine, or dust 
graphite, produced in the grinding process is not suitable for crucible 
work, owing both to its fineness and to its containing a great deal of the 
gritty impurities originally present in the graphite. This dust is generally 
disposed of to the foundry facing and other trades. 

It may be noted that the grading, or " curing," as it is termed, of graphite 
at the compounds in Ceylon, before shipment to the coast, is done entirely 
by hand and consists in chipping the impurities from the lump material, 
and in washing and sizing the various grades produced. What is known 
as Lump No. 1, or " Ordinary Lump " (abbreviated to O.L.) is therefore 
the purest material shipped, outside of one or two special high carbon 
grades for which there is only a limited market. Most of the imports 
of Ceylon graphite into the United States in 1917 consisted of Lump No. 

1 Thonindustrie-Zeitung, 1895, No. 3. 



133 

1 and Chip No. 1, as under existing ocean tonnage conditions and freight 
rates these grades were the most economical to import. 

Flake graphite, though purchased on a basis of an understood 90 per 
cent, or approximately 90 per cent, carbon content and a size of flake of 
from 20 to 90 mesh, is usually re-screened previous to use and may even, 
in some cases, be re-ground in burr mills. A certain amount of fine dust 
is thus produced which is disposed of for other classes of work. Flakes 
of more than ordinary size, i.e. much above 20 mesh, are not desirable, 
as they decrease the density of the crucible and detract from its strength. 

The sand used in small amount (about 10 per cent) in steel crucible 
mixtures is a clean, fine-grained quartz sand, while the burnt fireclay or 
grog used in brass pots has already been referred to above. The sand serves 
to diminish shrinkage of the crucible body, while the grog tends to keep 
the body open and, by permitting the escape of steam or gas during burning, 
to prevent cracking or bursting. 

The cleaned and sized materials are first of all weighed and charged 
in the proper proportions, together with water, to a pug mill or mixer 
holding about two tons, where they are thoroughly incorporated. After 
mixing, the dough is kneaded by hand into lumps of the required -size. 
Before being worked up in the pug mill, the dry materials may be sprinkled 
with water and left to become thoroughly impregnated with moisture, 
though this procedure is a matter of individual rather than general practice. 
The lumps of kneaded material are sometimes allowed to season for several 
weeks, and when commencing to show a dry surface crust, they are again 
worked up in a pug mill to a homogeneous mass. 

The material is now ready to be moulded into crucibles. In American 
practice, crucibles are made almost entirely by mechanical means, though 
the original practice was to form them by hand. The appliance used is 
styled a jolley and jigger. 

A given weight of the mixture is taken, kneaded by hand into a ball 
and placed in the mould which stands on a mould board base on a revolving 
table. It is then tamped down flat with a wooden pestle, the table is 
set revolving and a small, curved arm, known as the rib or jigger, attached 
to a vertical shaft, is lowered into the mould. On meeting the clay mixture, 
the rib forces or squeezes it upward between itself and the wall of the mould. 
The rib sinks at a distance from the mould required to form a crucible 
wall of the desired thickness and to a depth that will give the proper thick- 
ness of bottom. The necessary adjustment for the purpose can all be 
readily made on the machine, so that the whole process of moulding is 
practically automatic, and the same machine can be used to make pots 
of various sizes. As the weight of clay mixture necessary to form a pot 
of a certain size is known, there is practically no surplus forced up out of 
the mould. The top edge of the crucible is then smoothed off by hand, 
and the lip formed by cutting out a small piece with a tool made for the 
purpose. 

The moulds are made in two vertical halves, provided respectively 
with tongue and slot to ensure proper junction when set up. The moulds 
are formed by building up a sheet iron casing around a solid model of the 
size and shape of the exterior of the crucible to be made, a space equal to 
the desired thickness of the mould wall being left between model and casing. 
This varies of course with the size of the mould, and must be sufficient to 
give the mould the necessary strength during handling. Two metal strips 
are inserted in this space, half way around the periphery, so as to divide 



134 

the space into two equal halves, and plaster of Paris is then poured in, 
the solid model being first well soaped to prevent sticking. When this 
is set, the mould is removed and finished off to the exact size by turning 
and trimming. The mould is open at the bottom and rests on a mould 
board during formation of the crucible. The two halves are held together 
during this process by means of flexible straps of steel or other material, 
provided with brass clamps for tightening. After finishing, the crucibles 
remain in the moulds for a few days to harden sufficiently for handling, 
and are then removed and piled in tiers in large drying rooms, where they 
air dry for from 4 to 9 weeks, according to the size of the pot. From here 
they are taken to other drying rooms, supplied with hot air at 150°F, 
where they remain about a week, after which they are ready for the kilns. 
The shrinkage during drying usually amounts to from \" to f", measured 
along the diameter of the pot. After thorough seasoning, the crucibles 
are placed in large muffle kilns, about 15 feet in diameter, and heated at 
a temperature of from 1500° to 1800°F for from 30 to 48 hours, after which 
the kiln is allowed to cool off for five or six days before unloading. Muffle 
kilns fired with hard coal are preferred to the open, down-draught type, 
as the former dispense with the necessity of saggers and ensure a more 
uniform heating of the kiln's contents. Oil fired kilns, it is claimed, do not 
give as good results as coal fired, owing to the heat not penetrating uniformly 
to the centre. 

The following notes on the raw materials for crucibles and the manu- 
facture of crucibles are taken from Searle, " Refractory Materials," 1917, 
pp. 304-325. The details given relate, in the main, to English practice: — 

Plumbago crucibles are usually made of equal parts of clay and graphite, but some 
are made of 1 part of clay and 3 or even 4 parts of graphite or coke, whilst crucibles for 
steel and very sensitive alloys contain only 6 per cent of carbon, usually in the form of 
coke dust. The graphite has a much lower relative weight than clay and so occupies 
a much larger volume than its weight suggests. A mixture which is extensively used in 
Germany consists of 36 parts of fireclay, 23 of coarse grog, 23 of powdered coke and 18 of 
graphite. 

In steel manufacture, crucibles hold 75 to 80 lbs. of metal and are made chiefly 
of a mixture of fireclays. The proportions of the ingredients vary with the quality of steel 
to be made. The following mixtures are used by firms of high standing: — 

Crucible Mixtures for Various Metals. 



Hard 


Mild 


Razor 
steel. 


Very 


Copper, 




steel. 


steel. 


pure 


alloys, 


Cast 


(German) 


(German) 


steel. 


brass, etc. 












a 


b 


a 


54 


40 


12 


3 


8 


12 


53 


36 


38 


40 


87 


67 


50 


43 


36 


38 


40 


10 


67 


13 


43 


10 


22 


8 


10 


25 


25 


4 



Graphite or coke 

Fireclay 

China clay 

Grog 



Some brass foundries prefer crucibles with 50 per cent of graphite. 

The fine particles should be removed from the grog by passing it over a 40-mesh 
sieve and rejecting what passes through the latter. Crucibles in which no fine grog is 
used are more durable than others. 

The following mixtures are largely used in Sheffield, but it must be clearly under- 
stood that each maker works according to his own ideas and alters his recipes whenever 
there appears any advantage in doing so : — 



135 
Crucible Mixtures for Steel. 

A B C D E F 

White china clay 10 20 20 15 

Stourbridge clay 46 40 20 33 47 

Derby clay 20 18 13 23 .... 40 

Stannington clay 20 18 40 23 47 28 

Coke or plumbago 4 4 7 6 .... 4 

Grog 6 28 

When a high-carbon steel is to be made, the crucible may contain more graphite 
than when a mild steel is to be produced. Crucibles with a high content of graphite are 
objectionable for melting steel, as the metal absorbs flakes of graphite, which become 
enmeshed in it, producing small holes, flaws and weak places in the casting. As crucibles 
containing graphite last longer, they are cheaper to use than those made exclusively of 
clay. They are employed for all but the highest grades of crucible steel, the proportion 
of graphite (or coke dust) diminishing as the quality of the steel increases. 

Though nearly every steel melter has his own mixture for crucible manufacture, all 
agree in preferring several clays rather than a single one, no matter how refractory its 
character. 

The various materials, in the correct proportions, must be mixed with water to form 
a stiff uniform paste. There are several methods of doing this, but the ones most generally 
used are treading, panning and pugging, the first named being chiefly for large crucibles. 

When the materials are to be mixed by treading, they are spread out on a concrete 
floor and are sprinkled with water. The mass is turned over repeatedly with spades and 
when it becomes too pasty to be worked in this way, it is again spread out and is trodden by 
men with bare feet, who squeeze the clay between their toes, and so mix it thoroughly. 
Each portion of the material has to be squeezed between the toes, compressed and then 
pressed on to the previously worked paste. 

The trodden mass is then made up into balls of 40 to 45 lbs. weight, and is afterwards 
beaten into a dense mass. In some works it is pugged after being trodden. 

Various firms have endeavoured to replace this labour by means of pug mills or open 
mixers, but without much success, the makers declaring that clay mixed mechanically 
does not suit their purpose so well as that which has been trodden. The reason for this 
is difficult to understand, as a mechanical mixer effects a much better distribution of the 
particles and produces a sounder mass. 

French crucible manufacturers mix the dry materials together and then pass them 
through a pug mill, water being added to the contents of the latter by means of a sprinkler. 
The paste is allowed to spur for several days and is again passed through a pug mill, this 
process of souring and pugging being repeated several times. Some German manufacturers 
adopt this method for all crucibles. It is also used extensively in the U.S.A., though in 
the latter country, crucibles made from a semi-dry material are popular. 

The author has made careful microscopical and other tests of the same materials 
treated (a) by treading and (b) in a trough mixer and has always found that the mechan- 
ically mixed material is more uniform and homogeneous in texture than that which has been 
trodden. Yet so conservative are the users of steel crucibles and so serious is the loss 
occasioned by defective ones, that only a very small number of firms use a mechanical 
mixer, notwithstanding the fact that it can be made to produce a better material at a lower 
cost. 

For small and medium sized crucibles, the materials are mixed in a trough mixer 
or pug mill, or preferably by panning. For the latter purpose, sufficient quantities of each 
material to form a charge for a pan mill are weighed out, placed in the mill and the latter 
is set in motion. The necessary quantity of water is then added slowly through a sprinkler 
attached to the mill and the pan is kept in motion until the materials are properly mixed. 
In most cases, half an hour's treatment is sufficient, but for special crucibles the mixture 
is sometimes panned for several hours. 

A pan mill, or tempering mill, consists of an edge runner mill with a non-perforated 
(solid) revolving pan. The construction of a tempering mill resembles an edge runner 
grinding mill but it is much lighter, and the runners are supported on bearings, so that they 
rub rather than crush the material. 

The paste is allowed to remain in cellars for several days in order that it may sour 
and its plasticity be fully developed. At the same time it may, if too soft, be allowed to 
dry partially, so as to produce a paste of the desired stiffness. The paste may then be 
placed in a small pug mill, the material passing out of the latter being cut into clots each 
large enough for one crucible. Some makers pass the paste twice or three times through 
a pug mill, but so thorough a treatment is not usually necessary. 
67945—10 



136 

The souring is an important part of the preparation of the mixture, during which the 
clay becomes more plastic, the moisture is distributed uniformly and various chemical 
reactions occur. The effects of souring are increased if the material is pugged repeatedly 
during the souring stage. 

During the souring, the surface of the paste is prevented from drying by covering 
it with cloths which are kept constantly wet. 

The mass used for crucibles should be as dry as possible consistent with good working. 

Crucibles may be made (1) by hand in moulds, (2) by throwing on a wheel, (3) in 
jiggers and jolleys, (4) in presses, or (5) by casting. 

Jiggers and jolleys are specially used for plumbago crucibles, but if granular plumbago 
is one of the ingredients the material should be in an almost dry state and should be shaped 
in a wooden mould. Flaky graphite is not subject to this limitation. 

Hand-moulding is usually confined to the larger crucibles, as it is a slow and somewhat 
costly process, but gives excellent results. In making crucibles for melting steel, the wooden 
or cast iron moulds are technically known as flasks. They consist of an outer flask, the 
inside of which is the shape of the exterior of the crucible, but has an opening rather more 
than an inch in diameter at the bottom. The interior portion or stopper forms the core 
of the mould and is provided with a handle, so that it may be worked about until the paste 
in the flask is properly compressed into shape. The stopper has a projecting piece on the 
bottom. This passes through the hole in the bottom of the flask, and serves as a pivot 
and to keep the core in position during the shaping of the crucible. Unless the plunger is 
guided by the projecting piece, it is difficult to make large crucibles of regular shape. 

The flask is well oiled, the paste put into it and then gradually forced to the desired 
shape by inserting the core and working it to and fro in a rotary manner. If desired, the 
clay may be added in several portions instead of all at once, each addition being worked 
into place before the next is added. 

When the paste has been properly compressed, any superfluity is cut off, the core or 
stopper is withdrawn and a blunt knife is inserted between the clay and the outer flask 
so as to form the contracted mouth of the crucible, enabling it to be more readily covered 
in the furnace, protecting the surface of the metal to some extent from oxidation and serving 
several other useful purposes. Some makers prefer to effect this shaping of the mouth 
of the crucible after it has been taken out of the mould by rotating it on a small table, 
somewhat resembling a potter's wheel. 

The greatest care must be taken in filling up the hole at the bottom of the crucible 
and in making good defects in any other portions. It is always difficult to secure an 
absolutely satisfactory joint or patch and any carelessness in this respect may lead to the 
loss of a considerable quantity of molten metal. 

In another method of hand moulding, the mould consists of a block of dense, close 
textured wood, which is covered with a wet cloth free from loose threads. The mixture 
is thrown on this with some force and in small handfuls at a time, until a solid and uniform 
mass of suitable thickness is obtained. The mass must be repeatedly kneaded and stabbed 
so as to secure the absence of weak places, air bubbles, etc. The thickness of the bottom of 
the crucible should be about twice that of the sides. The bottom of the crucible being 
prepared, it is lifted on to a sanded board, placed quite level and covered with a linen disc. 
The drum or sides of themould is fastened to the board and the paste worked around the sides. 
If the crucible is sufficiently large, this may be done with the feet; otherwise, the hands or a 
small rounded stick is employed. The surface is then roughened with an iron comb and 
fresh clay thrown on to the mould, handful by handful, until, after sufficient kneading and 
working the mould is lined with* paste to the requisite thickness. The inner surface of 
the crucible is then smoothed with hand tools. 

In a third method of moulding crucibles by hand (this is a combination of hand 
moulding and throwing) the clay paste is thrown on to a hollow wooden core, the shape of 
the interior of the crucible and mounted on a vertical steel spindle so that the core may be 
rotated by hand or power. The workman forms the outside of the crucible by working 
the paste with his hands or with a tool at the same time as the core rotates. A sliding verti- 
cal gauge or a profile may also be used to ensure the crucible being accurate in shape and 
thickness. When the shaping is finished and the crucible smoothed, the core is lifted 
from the spindle and inverted over a board. The crucible then easily slips off the core, 
and the latter is again ready for use. A linen cover may be put over the core to facilitate 
the removal of the crucible. The pouring spout is made by pressing part of the edge 
of the crucible between the thumb and fingers. 

Plaster cores are occasionally used in this method instead of wooden ones, but they 
are costly and not particularly advantageous. The chief reason for their use is that the 
crucible separates more readily from plaster than from wood, but with a skilled workman 
plaster confers no advantage. 



137 

Crucibles are made in large numbers by means of a jolley and jigger. A piece 
of paste is placed in a plaster of Paris or iron mould, which is then rapidly rotated, and a 
profile or jigger is pressed on to the clay so as to make it to conform to the interior of the 
mould and produce a crucible the walls of which are of the requisite thickness. The 
mould is then removed from the machine and taken to the dryer, its place being taken by 
a fresh one. This is a good method, but somewhat costly, owing to the frequent renewals 
of the plaster moulds. It has also the drawback that the clay paste must be very soft 
and the crucibles are not as dense as desirable. 

Hand presses are more suitable for small crucibles and scorifiers, but are occasionally 
used for large ones. They consist of a plunger and lower mould or die, the paste being 
placed in the die and then compressed by the plunger. 

In power driven presses either the plunger or die, or both, may be made to rotate 
during the application of the pressure. This prevents the adhesion of the paste to the 
metal. A large number of different presses have been suggested for the manufacture of 
crucibles, but most of them are unsatisfactory because they make the various parts of the 
crucible irregular, some being much denser than others, thereby setting up strains and 
cracks. The author has made an extensive series of trials with all the advertised presses 
(both British and foreign), and has concluded that the most suitable press consists of a 
rotating plunger and a loose mould which is lifted by a treadle to the plunger. The sides 
of the plunger are slightly flattened and grooved so as to permit the escape of air between 
the plunger and the clay. The mould or die is carried on a plate which can be rotated on 
an oiled bed or on ball bearings. This plate is not driven mechanically, but is caused to 
rotate by the friction between it and the clay. To use such a machine a piece of stifhsh 
clay paste of suitable size is dipped in paraffin and placed in the mould. The treadle of 
the machine is then depressed and the mould is lifted until the clay is forced against the 
rapidly revolving plunger. As the mould rises, the clay is gradually squeezed into the 
desired shape and the friction causes the mould to rotate rapidly. Finally, when the 
mould has reached its highest point, the surplus clay is cut off automatically by the pressure 
of the top of the mould on the lower side of the plunger head and the treadle is then released. 
The mould then descends and, when a suitable point is reached, a stop comes into operation 
and prevents the crucible from descending further, while permitting the mould to do so. 
The crucible is then removed and the machine is ready to make another. A daily output 
of 6,000 crucibles, each 6 inches or less in diameter, or 1,400 crucibles of 12 inches diameter, 
can easily be obtained with one of these machines and two strong youths. The clay is 
supplied in the form of discs, which are made in a small pug mill fitted with a circular 
mouth piece and a wire-cutting table. This arrangement saves the necessity of weighing 
out the clay. 

All machines with plungers and dies which do not rotate appear to be unsatisfactory 
for any but the smaller sizes of crucibles; as their output is lower, the quality of the crucibles 
is inferior and much trouble is caused by the adhesion of the clay to the metal. 

In all mechanical presses used for crucibles it is necessary to dip the lump of paste 
into paraffin or other lubricant, unless the mixture is so rich in graphite that no other 
lubricant is needed. Unless the clay is well lubricated, it will adhere to the metal of the 
machine, and will cause difficulty in making crucibles of good shape. 

At the present time, the use of a jolley and jigger is by far the most popular method 
of making crucibles, but as the value of the more recent mechanical presses and methods 
of casting become more appreciated, there can be no doubt that they will be used more 
extensively. 

The best crucibles are usually finished or fettled by rubbing the surface with a wet 
sponge and with leather or rubber so as to make it smooth. Sometimes they are washed 
with a slip of fine clay so as to produce a fine coating inside. This treatment makes the 
crucibles more resistant to slags, etc., as it is similar to a special lining. 

Crucibles must be dried slowly and uniformly, or they will crack when in use. It 
is specially necessary to protect them from all draughts and from direct sunlight, as these 
would cause fine cracks. They are usually dried on racks in rooms heated by steam pipes 
or by heat radiated from the kilns or ovens in which the crucibles are to be burned later. 
In some works the crucibles are first placed in a room kept at 30°C (86°F), and are then 
transferred to another kept at 50°C (120°F), where they remain for a fortnight or more. 

Another method of drying consists in placing the crucibles on racks in small unventi- 
lated chambers or stoves, which are then heated by steam until the crucibles are almost 
dry. The drying is completed by stacking them on racks around the kiln or oven. 

Crucibles for melting steel are usually placed on shelves around the walls of the shop 
in which they are made, each shelf being wide enough to hold two or three rows. They 
are turned occasionally, and, when nearly dry, may be taken to the furnace room, where 
they are stored on shelves until perfectly dried by the heat radiated from the furnaces and 
castings. 

67945— lOi 



138 

Direct heat should be avoided in drying and crucibles for steel should not be placed 
too near the fire until they are perfectly dry. This takes about three months in all, the 
first month being spent in the making room and the last two in a store, where a small amount 
of heat may be admitted. The longer the crucibles remain untouched, the better they are 
likely to prove in use, so that prolonged storage is more profitable than it appears to be 
at first sight. 

When plumbago crucibles are properly dried they should emit a clear metallic tone 
on being struck. 

Dry crucibles must be kept in a warm place, as they are very sensitive to frost. On 
no account should they be stored in an open shed. 

Where crucibles are manufactured in the works in which they will afterwards be 
used, they are not burned in kilns, but are warmed through in the furnaces in which they 
are to be used, or in a preliminary furnace consisting of a long, low chamber with a fireplace 
at one end on which coke is burned. The hot gases from the coke pass through the chamber 
containing the crucibles and away to the chimney. During the warming through, the 
crucible should be placed upside down on the fuel, as this reduces its tendency to crack. 

Crucibles which are made for sale and for transport over considerable distances must 
be burned in order to give them sufficient strength. The temperature at which this burning 
is effected Mall depend on the purpose for which the crucibles are to be used. The majority' 
of crucibles should not be burned very hard, though the longer they are heated to bright 
redness the greater will be their durability. If insufficiently heated, the crucibles will be 
weak and will need more careful treatment during the first heating than is usually bestowed 
upon them. 

Plumbago crucibles are usually burned at 710°C to 900°C (Seger cones 018 to 010a) 
in muffles or saggers packed with coke-dust or sand, to prevent the undue combustion of 
the graphite. According to the patent specification published by D. B. Williams and J. R. 
Stauffer in 1904, the carbon monoxide and other gases evolved in this treatment penetrate 
the crucibles and convert the clay into a very refractory substance. 

If a plumbago crucible has become reddened, by the oxidation of any iron present, 
it is given a coating of black lead to restore it to its proper colour. 

The temperature in the kiln must rise very gradually, particularly at first. For 
forty-eight hours it should not exceed 110°C, the final temperature being reached after 
a further forty-eight hours or more. 

It is essential that crucibles and scorifiers should be (a) sufficiently refractory to 
withstand any temperature to which they are likely to be exposed, (b) unaffected by rapid 
cooling, (c) sufficiently dense to cause no loss of contents by absorption, (d) sufficiently 
resistant to the corrosive action of the contents, particularly metallic oxides, slags and 
ashes, (e) sufficiently strong to hold the contents safely, e.g., a crucible full of steel weighs 
about half a hundredweight and it is necessary to carry such crucibles full of molten metal 
for considerable distances. It is extremely difficult to produce crucibles having all these 
properties in a high degree, especially when large crucibles are required. 

The greatest damage is done to crucibles by the use of unsuitable tongs or by handling 
the tongs improperly. If they do not fit the crucible properly, or grip it too tightly, they 
will produce severe strains which rapidly reduce its durability. The heat of the furnace 
soon causes the tongs to lose their original shape, so that they should be tested frequently 
against an iron disc turned to a suitable shape. This involves very little trouble and greatly 
increases the life of the crucibles. 

Large crucibles should be lifted out of the furnace by some kind of block tackle, 
as this strains them less than when men lift them by means of tongs and handhooks. 

An oxidising atmosphere will burn the graphite from the outside of the pot and 
weaken it; hence, for a long crucible life in any furnace, especially in oil or gas fired ones, 
a reducing flame should be maintained. 

It is clearly impossible to give any accurate figures showing how many times a 
crucible may be used. Some men can use a crucible eighty times or more for cast iron, 
whilst others can only use a similar crucible half a dozen times. Similarly with the melting 
of alloys, steel, and all other purposes for which crucibles are used, the manner in which the 
tongs fit and the handling of the crucible being much more important than is usually 
imagined. The following figures represent fair averages : — 

For brass, a crucible should serve 70 to 100 times. 
For bronze, about 50 times. 

For iron, " 70 to 90 times. 

For steel, 6 to 10 times. 



139 

With regard to the qualities desired in a graphite crucible, W. J. 
Downs gives the following notes 1 : — 

The requisites of a good graphite crucible are refractoriness, strength, heat 
conduction, long life — i.e., capability of standing many heats — and resistance to the 
action at high heat of materials in contact within or without. The refractory quality 
of a crucible is much misunderstood. It is not so difficult to arrange for the refractory 
quality alone as for the other requisite qualities of a good crucible. A mixture of graphite 
and high grade fireclay would give a mixture refractory enough to stand the fusion of plat- 
inum but would utterly fail in the other requisites. 

The range of refractoriness of a graphite crucible is very great. The crucible giving 
good service at the temperatures of nickel fusion is not well adapted for service in spelter 
castings. This means that the mixture has to be varied according to the temperature of 
the service required. This would not be the case if the refractory quality were not so 
intimately associated with the other requisites of a good crucible. The graphite in the wall 
of a crucible begins to oxidize at a temperature of about 600°C. Its rate of oxidation 
increases with the temperature and varies with the composition of the furnace gases. The 
life of the crucible depends largely on the non-oxidation of the graphite. This is prevented 
by the production of a glaze on the outer surface of the crucible. The production of this 
glaze depends on the refractoriness of the crucible mixture. Hence, if the material be too 
infusible, the life of the crucible is very much shortened. On the other hand, if it be too 
fusible, it softens and fails utterly. The production of the glaze depends on the component 
parts of the crucible mixture, the temperature of service and the nature of the fuel used. 
Some users coat the outside of the crucible with a mixture more fusible than the wall of the 
crucible itself. If the first heat to which a crucible is subjected is high enough to produce 
this protective glaze, its life at lower subsequent heats is much prolonged. 

It is usually more difficult to make a good crucible for low heat service than for high 
heat work, though this is not so much due to the crucible maker as to the fact that low heat 
fusions are apt to be overheated. Hence, a crucible should not be too refractory, but should 
be so made that oxidation of the graphite is prevented at the temperature and condition 
of service and yet kept strong enough to stand the burden of metal and the handling it is 
to receive. This last remark has its bearing on the size of the crucible in relation to strength. 
It is possible for a crucible to fill all the requirements and not be able to stand the burden 
of the metal it is capable of holding, nor the more severe strain of handling by tongs. 
Every such handling shortens the life of the crucible, and the movement in the direction 
of the adoption of various types of tilting furnaces for large crucibles shows that the users 
of crucibles are appreciating this point. 

Graphite crucibles may be classified according to the kind of metal to 
be melted and the kind of fuel used, the different types varying in shape 
and also in composition. The principal division is into (1) steel crucibles 
and (2) brass crucibles. Other metals or alloys are melted in one or the 
other of these two types. According to the class of fuel used, crucibles 
may be divided into gas, coke, and coal. 

The general shape of all these as made in the United States is that of 
an egg cut off flat at each end. The steel crucibles are of nearly the same 
diameter at each end or are often smaller at the top, and the bilge or 
greatest diameter is a little more than half way up. The brass crucibles 
are of the same general shape, except that the diameter at the top is con- 
siderably greater than at the bottom, the bilge being about in the same 
position. The ratio of diameter to height is less in steel than in brass 
crucibles, and this is more pronounced in the foreign makes than in American 
pots. The narrower crucibles are more economical in fuel than the broader 
American type. 

Many special shapes are made to suit special work or furnaces, but 
the egg shape is the prevailing one for ordinary work. The notation of 
the size of a graphite crucible is quite arbitrary and has changed from time 
to time. It is based on the capacity of the crucible in pounds of metal and 
is expressed in numbers. At present the unit of size of a brass crucible is 

1 Iron Age, May 10, 1900, p. 10. 



140 

3 pounds per number; that is a No. 60 crucible has a capacity of 180 pounds 
of metal. As the specific gravity of the metals and alloys melted in these 
crucibles varies, the capacity in pounds also varies, but the metal in whose 
terms the capacity is expressed is ordinary brass, having a specific gravity 
of about 8. A No. 70 crucible will melt 200 pounds of bronze, 250 pounds 
of silver and 350 pounds of gold. The following table showing the standard 
sizes of graphite crucibles, as approved by the American Institute of Metals, 
is taken from Vol. X of the Transactions of the Institute, 1916, p. 5: — 

Standard Sizes for Graphite Crucibles. 



Number. 



Height. 


Top. 


Bilge. 


» 


n 


// 


8^ 


6! 


6! 


8f 


7 


7| 


9* 


71 


71 


10 


7* 


8 


10| 


71 


8* 


11 


81 


9 


11* 


81 


91 


m 


91 


10 


12| 


91 


10* 


131 


10 


101 


13* 


101 


11* 


14| 


10| 


11* 


14| 


101 


12 


15* 


11* 


12* 


16 


111 


121 


16* 


121 


131 


16f 


12* 


14 


19 


13* 


14| 


191 


14f 


16 


20| 


15 


161 


20| 


15 


161 


21 


15* 


171 


22* 


15 


17* 


22J 


161 


17| 


24* 


17* 


19* 



Bottom. 



12 

14 

16 

18 

20 

25 

30 

35 

40 

45 

50 

60 

70 

80 

90 

100 

125 

150 

175 

200 

225 

250 

275 

300 

400 



8^ 



10 

lot 

n 

Hi 

12* 
HI 
12* 
121 
14 



Steel crucibles are usually made in two sizes only, viz., No. 50 and 
No. 60, and the size numbers do not correspond to the capacity of melted 
metal. A. No. 50 steel pot has a capacity of about 95 pounds, and No. 60, 
about 110 pounds. 

Another and larger type of graphite crucible is the retort used in the 
distillation of zinc in silver refineries. These retorts range from 31 inches 
to 40 inches in length, with a bilge of from 16 inches to 22 inches, and are 
used in furnaces of the tilting type. Still another type of crucible is 
designed for the tempering of files. 

The number of heats that a brass crucible may be expected to stand 
is essentially dependent on the materials used in its composition, the care 
taken in its manufacture and the handling it receives in service. Even the 
best of crucibles, that is, a crucible made from the best materials and with 
the greatest attention paid to their proportioning and mixing, will have its 
life very materially shortened by careless handling, while careful treatment 
may secure a relatively large number of heats from a poorer grade of pot. 
Equal care on the part of both the maker and the foundry man is essential, 
therefore, to secure best results. It is due to the failure in many foundries 



141 

to observe the proper precautions in the use of crucibles that so little really 
reliable data on the quality of the pots made from substitutes for German 
clay and Ceylon graphite is available. American crucible makers report 
the most divergent opinion from their customers on this point. 

In this connexion, it may be again noted that of the two principal 
ingredients of a crucible mixture, graphite and clay, graphite is used because 
of its refractoriness and good heat conductivity. It has no binding qualities 
whatever, and it oxidizes readily under high temperatures when exposed 
to the air. The clay serves as a binder to hold the graphite particles 
together, and even before having the necessary amount of water of plasticity 
added to it, and in its natural state, under ordinary atmospheric conditions, 
contains an appreciable amount of moisture. The total amount of water 
in a crucible when newly made is about 20 per cent, and the slow drying 
process that crucibles undergo before burning dispels the mechanically 
added water, or water of plasticity, but not the hygroscopic moisture. 
The latter is driven off in the burning process, the object of which is to 
calcine the clay. On removal from the kiln, the crucible immediately 
begins to absorb hygroscopic moisture and continues to do so until saturated. 
Just how much moisture will be taken up, obviously depends on the humidity 
of the air surrounding the crucible. A test made on a crucible that, when 
taken from the kiln, contained less than 0-25 per cent moisture, showed 
that after standing for four hours in a room at 90°F, the moisture content 
had risen to 2 • 7 per cent. After a further five hours under ordinary atmos- 
pheric conditions of average humidity this had increased to 4 • 5 per cent. 

It is clear that by subjecting a crucible that has stood for some time 
exposed to ordinary atmospheric humidity to sudden heating, the absorbed 
moisture will be expelled violently in the form of steam, with attendant 
damage to the crucible. Such a procedure often results in what is termed 
scalping, i. e. the breaking away of a section of the crucible wall or the 
flaking off of irregularly shaped pieces (see Plate XLV) . Even if no actual 
fracture is evident, internal cracks or lines of weakness may develop, 
resulting after a few runs, in leaks or pin holes. 

Scalping may also result from one portion of the crucible being heated 
to a temperature considerably higher than that of adjoining portions, 
when the unequal expansion causes the crucible to fly. 

In order to prevent the absorption of more than a minimum of hygros- 
copic moisture, crucibles should be stored in a warm, dry room kept at a 
temperature of preferably 10Q°F, for at least four weeks before using. 
By adopting this precaution, the risk of blowing or scalping is reduced to a 
minimum. 

The annealing of crucibles at the foundry, that is, the preliminary 
warming up before being subjected to the full heat of the furnace, is various- 
ly carried out and often in a manner detrimental to the crucible. The 
best device for annealing purposes is an oven built expressly for the 
purpose, using the wasted heat from the furnace on the way to the stack. 
These can be built so that the heat can be controlled and the temperature 
brought gradually to 250°F or beyond. The average size crucible, say 
a No. 60, should be kept at the above temperature for at least 48 hours 
before being placed in the furnace, while larger sizes require still longer. 
The common practice of annealing crucibles in core ovens, where they are 
exposed to the moisture driven off from the cores, is a frequent cause of 
failure to secure proper service. 



142 

Allowing a crucible, at the end of a day's rim, to remain in the furnace 
and to cool down with the fire often materially assists in prolonging its life. 

A practice sometimes followed in order to dry out crucibles before 
heating is to make a small fire of shavings and charcoal inside the pot a few 
hours before use, but this is, at best, only a makeshift and does not give 
as good results as annealing in a proper oven. Careful handling with the 
tongs also plays an important role in a crucible's service. In tilting furnaces, 
where the constant lifting in and out is eliminated, a crucible will often 
run more than double the average number of heats. When a crucible is 
lifted from the furnace with its load of melted metal it is plastic and readily 
adjusts itself to the shape of ill-fitting tongs. After pouring and cooling 
off, this shape is retained, and unless the tongs happen to be applied in 
exactly the same position at the next pour, the crucible will again be 
distorted. Such repeated treatment will seriously weaken the crucible and 
shorten its life. 

Tongs should never grip a pot above the bilge but should extend below 
it to within six inches or so of the bottom. A crucible is made heavier here 
for this purpose and the bilge helps to withstand the strain of the tongs. 

Improper fuel, too, is extremely detrimental to crucibles, the gases 
from such fuels, especially from those high in sulphur, penetrate the crucible 
wall and cause serious alligator cracks to develop. This is especially 
pronounced in the case of wet or damp fuel, either coal or coke. Imperfect 
combustion with oil or gas will also have this result. These gases are 
always produced at low temperatures, usually in a coal or coke fire imme- 
diately after a fresh charge of fuel, and in oil and gas furnaces at a slight 
adjustment of the air or fuel valves. 

Allowing the crucible with its melted charge to remain longer than 
necessary in the furnace is also bad practice. Such procedure is known as 
soaking, and obviously shortens the life of the crucible by burning up the 
graphite in its walls, besides weakening it in other ways. 

The following remarks on methods of securing better service from 
graphite crucibles are from a publication of recent date. 1 

Back in June, 1916, the crucible situation became most serious, due to increased 
demands on the part of crucible steel and munition makers, together with lack of certain 
kinds of material entering into the make up of the crucible, and prices soared from 4 cent3 
to 25 cents a number. Among others that encountered unpleasant inconveniences was 
the Portsmouth Navy Yard smelting plant, with 26 crucible furnaces in operation, getting 
one, two, and sometimes three heats per crucible; this trouble covering a period of about 
four weeks. The many attempts to increase the life of the crucible became discouraging, 
the only consolation being in the fact that the trouble was universal, and up to maker and 
user to tax his wits to master the situation if possible. Something had to be done quickly 
to save the day at the smelting plant where the nonf errous scrap metals from all the yards 
are sent to be put into ingot metal for reuse at the various navy yard foundries. 

The writer undertook to solve the problem of preventing the flaking and cracking 
of the crucibles, and in one week's time succeeded in overcoming the difficulty by three 
simple moves : — 

1. Getting away from core oven annealing. 

2. By a preparation of coating (our own make) and annealing in the furnace pit, 
drawing our supply from that source as needed. 

3. Using a flux that prevented cleavage of slag and metals to the inside of the crucibles, 
with the result : — That the life of the crucibles went up to 20 heats immediately, and, as 
our records show, to 30 heats for the latter part of 1916. 

From January 1, 1917, to May 1, 1918, the supply department invoiced to the smelt- 
ing plant 376 No. 100 crucibles. The number of heats from January 1, 1917, to May 1, 
1918, amounted to 20,295, giving a total average of 54 heats per crucible. The fuel used 

1 T. F. Durning, in the Brass World, August 1918, p. 227. 



143 

is hard coal, with coaling space around crucible 2| in., and with a sufficient coal bottom to 
carry through the heat without recoaling or disturbing crucible until drawn for pouring. 

|^ The various kinds of work in which graphite crucibles are used as the 
melting vessel include malleable castings, small iron castings, crucible 
cast steel, all kinds of copper alloys, spelter castings, file tempering, gold 
and silver melting and refining. Oblong, square, and round shapes, also, 
are used in liquid brazing, and as calcining trays or boxes for materials 
requiring careful, even heating, without exposure, such as pencil leads, 
incandescent light carbons, etc. The graphite retorts or flasks used in 
the distillation of zinc in silver refining works have a holding capacity of 
1,500 pounds of metal. (Plate XLIX). 

As already outlined, the principal advantage of graphite crucibles is 
their ability to stand sudden changes of temperature without cracking; 
they can be used repeatedly, until so much of the graphite is burnt that 
the pot cannot support the weight of the charge and handling with the 
tongs. Even when the graphite near the surface of the crucible has burnt 
away, that within the wall is protected for a considerable time by the 
coating of fused clay that envelops the particles and retards oxidation. 

Graphite crucibles are not so porous as clay crucibles, and thus do not 
absorb so much of the melted metal as the latter. For this reason they 
are to be preferred in the melting of precious metals. 

With regard to the future of the graphite crucible industry, it has 
already been noted that there is at the present time a decided tendency 
toward the adoption of the electric furnace for melting steel, and that this 
dispenses with the necessity for graphite crucibles for this class of work. 
In the brass industry, also, there are indications that electric furnaces may 
in the near future replace crucible furnaces. In this connexion, the follow- 
ing extract from an article by H. W. Gillett and A. E. Rhoads in the 
<'Brass World" is of interest. 1 

It seems inevitable that the next few years will see electric furnaces largely replacing 
crucible furnaces in the brass industry; a development comparable to that which the last 
few years have seen in the steel industry. 

With Klingenberg clay not available and Ceylon graphite requiring shipping needed 
for other purposes, crucibles, despite the good work done by crucible manufacturers, the 
Bureau of Standards, and others on the problem, are, speaking generally, still of much poorer 
quality, and many times more costly than they were under pre-war conditions. 

Besides the avoidance of crucibles and the ability to melt larger charges, electric 
melting (in a suitable type of furnaces) decreases the loss of metal by oxidation and by 
volatilization, prevents the taking up of sulphur from the fuel, gives better and more health- 
ful working conditions, and has many minor advantages such as freedom from handling 
and storing fuel and ash. Electric furnaces give crucible quality of metal without using 
crucibles. 

Tilting furnaces obviate the use of tongs for lifting the crucibles in 
and out, and in this way help materially to prolong their life. Tilting 
furnaces, however, are not suitable for many classes of foundry work and 
involve, in addition, considerable expense over ordinary crucible furnaces, 
since they hold only one pot, and thus a large number are needed. Crucibles 
for this type of furnace are made with a special lip for pouring. (Plate 
XLIV). 

Modified forms of the ordinary steel or brass crucible are the bottom- 
pour and self-skimming pots. In the former, the pouring edge is made 
extra thick and has a hole or spout extending downwards through it about 
two-thirds of the height of the wall. In this way, the metal is poured 

1 A Rocking Electric Brass Furnace, Brass World, August 1918, p. 217. 



144 

always from the bottom and no oxidized metal has a chance to get into the 
casting. The self-skimming crucible is designed for melting the precious 
metals, and is provided with a bridge at the pouring lip, which holds back 
the charcoal and molten fluxes and ensures clean metal in the pour. The 
bottom-pour type of crucible is illustrated in Plate XLVII. 

OTHER GRAPHITE REFRACTORY PRODUCTS. 

Besides crucibles, a variety of refractory articles used in smelting and 
foundry work contain graphite as one of their constituents. These articles 
include crucible covers, stopper heads for open-hearth and Bessemer steel 
ladles, pouring nozzles, stirrers, rings, jackets, stopper sleeves, crucible 
rests or stools, skimmers, dippers, phosphorizers, funnel or extension tops 
for crucibles, pyrometer shields, boxes for burning pencil leads and incan- 
descent light filaments and for case hardening and carbonizing, graphite 
furnace bricks, etc. A number of the above articles are illustrated in 
Plates L to LIII. 

Tempering crucibles for files and tool steel are of approximately 
the same diameter at top and bottom, a sample of size being, height 25" 
and diameter 9". The crucibles are filled with molten lead or chemicals, 
and the heated steel from the forge is immersed in the latter, so as to effect 
a gradual cooling. 

The brazing crucibles shown in Plate XL VIII illustrate some of the 
shapes used in the dip brazing of bicycle frames. 

Extension tops or funnels (Plate L) are placed on the top of crucibles 
in order to insert a larger charge of turnings or chips, thus reducing the 
necessity of frequent additions of small quantities of such material. 

Pyrometer shields (Plate L) serve to protect the pyrometer tube from 
contact with the metal or other substance under test. Those used in 
calibrating pyrometers are made entirely of graphite without clay admixture, 
in order to avoid contamination of the check metal. The same holds good 
for the graphite crucibles used in this work. Shields and crucibles for this 
line of work are usually made of artificial graphite. 

Phosphorizers (Plate LII) are used to introduce phosphorus into the 
metal in the manufacture of phosphor-bronze. An iron rod is fastened 
into the hole in the neck, and the phosphorus, securely wrapped to prevent 
spontaneous ignition, is placed in the lower chamber. The phosphorizer 
is then plunged into the molten metal. Phosphorizers need the same care 
as crucibles before use, that is, they require to be annealed in order to 
prevent cracking. 

Graphite bricks are used for lining certain portions of furnace walls, 
in order to prevent clinkers from adhering to them. 

Graphite is also added in some cases, to refractory cements, as it 
causes them to work more easily under the trowel. 

Graphite has been used, also, in the manufacture of the smaller sizes 
of retorts, using 2 parts of graphite to 1 part of fireclay. 

PENCILS. 

The manufacture of graphite pencils 1 on a commercial scale originated 

1 For fuller details of pencil manufacturing methods see the following: Haenig, A., Der Graphit 
1910, pp. 104-125; Hardmuth, L. and C, Die Bleistifterzeugung, 1902; Die Bleistiftfabrik von 
A. W. Faber, zu Stein, bei Niirnberg (an historical sketch, prepared for the Vienna Exhibition, in 
1873); Buchwald, A., Bleistifte, Farbstifte, farbige Kreide- und Pastellstifte, und ihre Herstellung, 
etc., 1904; Donath, E., Der Graphit, 1904, pp. 107-128; Cirkel, F., Graphite, Its Properties, 
Occurrence, Refining and Uses, Mines Branch, Department of Mines, Ottawa, 1906, pp. 253-276. 
The last contains most of the information given in the preceding works. This report is out of 
print, but may be consulted in many of the libraries of technical, engineering and scientific 
Societies, Government Mining Departments, etc. 



145 

with the discovery of the famous Borrowdale graphite deposit in Cumber- 
land, England. 

This deposit was discovered and worked in 1564, that is, in the reign 
of Queen Elizabeth. Much of the graphite here was of such purity that 
it could be taken out in large blocks and cut up into pencil rods, without the 
necessity of subjecting the material to any refining process. The graphite 
that was too much mixed with impurities in the form of other minerals to 
be suitable for pencils was used in the manufacture of crucibles. 

The high grade pencil graphite from the Borrowdale mine was so prized 
and brought such high prices that much trouble regarding titles and owner- 
ship arose and the Government was forced to assume control of the deposits. 
A period of six weeks was set as the maximum time during each year that 
the mine might be worked, and even under this limitation, the average 
annual output amounted in value to £40,000 or about $200,000. 

All of the graphite produced was sent to the graphite auctions held in 
London on the first Monday in each month, where it commonly brought 
as much as $40 per pound. In order to foster the new industry, the Govern- 
ment soon prohibited all exports of graphite except in the form of pencils. 

After the richer portions of the Borrowdale deposits were exhausted, 
an attempt was made to concentrate the poorer ore, but the material so 
obtained never equalled the richer grades of crude graphite. 

Borrowdale graphite was long known by the names black cawke and 
wad, the latter being the modern name of an ore of manganese. This 
deposit has long been exhausted, the last active work having been carried 
out in 1833. Some prospecting was conducted in 1875, and the graphite 
obtained is reported to have sold for $10 per pound. The mineral occurred 
in pipes, strings and nests, in association with a dike of altered diorite 
intruded into volcanic ash 1 . 

At about the time when the Borrowdale pencil graphite deposit became 
exhausted, an occurrence of similar mineral was discovered at Mount 
Batougol, in Siberia, and this deposit for many years supplied the Faber 
pencil factory at Nurnberg with all the graphite required. 

The first pencils consisted merely of rods of pure graphite cut from the 
massive material as it came from the mine. Later, these rods were inserted 
between two pieces of grooved wood, forming pencils of the same' type as 
those used at the present day, though they were probably larger and contained 
thicker leads. 

To obtain a harder lead, the graphite rods are reported to have been 
heated in molten sulphur before being placed between the wood strips. 
Pencils continued to be made in this manner up to 1795, when Conte 
devised the present method of manufacture, consisting in mixing finely 
ground clay and graphite together into a thick paste or dough from which 
the leads were moulded, and afterwards baking. By this means, a much 
more uniform product was possible, and by changing the proportions of 
clay and graphite in the mixture varying degrees of hardness were obtain- 
able. 

This method naturally effected a great saving in graphite over the 
old procedure,, which was very wasteful. Attempts had been previously 
made to eliminate the waste from the Borrowdale graphite mines by pulver- 
izing and subjecting it to a chemical process to remove gangue, after which 
the graphite sludge was pressed into a compact mass which could be cut 

1 Mem. Geol. Surv. Great Britain, Vol. V, 1916, p. 25; see also Haenig, op. cit., p. 41. 



146 

into leads in the same way as the natural mineral. This method did not 
prove successful, however, nor did later attempts to incorporate glue, 
isinglass, tallow, wax, and other bonding substances into the powdered 
graphite in order to form a compact, sectile mass. Equally unsuccessful 
was the experiment of mixing graphite with melted sulphur or antimony. 

At the present day, only the soft, earthy or so-called amorphous 
graphites are employed in the manufacture of pencils. The flake graphites, 
as well as Ceylon plumbago, do not possess nearly the same marking power 
as the earthy kinds, such as the Siberian and Mexican graphites. In 
American pencil factories, Mexican graphite forms the bulk of the graphite 
used. The Bavarian and Bohemian mineral is also suited to this purpose. 

The well known firms of Faber and Hardmuth, located respectively 
at Stein, near Ntirnberg, in Germany, and at Vienna, in Austria, were for 
years the largest pencil manufacturing concerns in the world, but in the 
early nineties, the industry obtained a foothold in America, and within 
three years the exports of pencils from Germany to the United States fell 
off almost one half. 

In 1909, the year of the last census, there were 11 pencil factories in 
the United States, employing 4,513 persons and paying out nearly two and 
a half million dollars in wages and salaries. The output of these factories 
was valued at almost seven and a half million dollars 1 . 

About 7 per cent of the total world's production of graphite is estimated 
to be consumed in the pencil industry. 

In modern methods of pencil manufacture 2 a soft, amorphous graphite 
is employed, since this material may more readily be ground to a powder 
consisting of uniform particles than a flake graphite, which, however 
finely ground, still preserves its flake form. 

Clay is used as a binder, and varying degrees of hardness in the finished 
pencil are secured by varying the proportions of clay and graphite in the 
mix. At the present day, much attention is devoted by manufacturers to 
producing extremely high grade pencils especially adapted to different classes 
of sketching and draughting work, and the correct mixing of the graphite 
and clay entering into the different grades is given the closest supervision. 
One celebrated firm in the United States offers seventeen degrees of hardness 
in its best grade of pencil, and the maintenance of strict uniformity through- 
out the different hardnesses requires the closest attention to the quality of 
the raw materials and their proportioning, as well as to the grinding and 
mixing. 

The graphite is first of all ground dry and then air-floated, after which 
it is floated on water, to remove grit particles. A high grade stoneware 
clay is used as the binder. This clay must be highly plastic and refractory, 
and free from iron and lime. A suitable clay should have the composition, 
approximately : — 

Silica 50-60 per cent. 

Alumina 50-40 " 

The clay is ground dry, water floated, and settled in tanks. Graphite 
and clay are then mixed in the required proportions and further ground 
between burrstones in a closed tank. This grinding is wet, and according 

1 This total may include certain side lines, such as erasers, pencil cases, pen holders, etc., but 
probably represents pencils for the most part. 

2 From information courteously supplied by the Joseph Dixon Crucible Co., Jersey City, and 
the Eagle Pencil Company, New York. 



147 

to the degree of fineness required, lasts from two weeks to three months. 
The sludge from the burr mill is then passed to a filter press or vacuum 
filter, preferably the latter, since the cloth screens of the former tend to 
clog. The product from the filter is kneaded by hand to the required 
consistency, and the dough is fed to hydraulic presses which force it, under 
a pressure of 2,000 pounds per square inch, through dies of the diameter 
of the finished lead. The lead issues from the die in the form of a continuous 
string, and the die head, being mounted on a toggle joint, the string is 
coiled as it exudes from the die and is caught in a shallow metal dish. The 
dish is removed when full, and the lead is uncoiled by hand and pinched 
off into lengths, each equal to three pencil lengths. At this stage, the 
material is quite tough and pliable and can be readily handled without 
breaking or deformation. The lengths of lead are laid between boards 
and allowed to air dry, after which they are cut by hand into pencil lengths 
and arranged in bundles in graphite crucibles or boxes. They are then 
placed in a kiln and baked for several hours at a temperature of 1,500° to 
2,000° F., after which they are ready to be placed in the wood casings. 
An intermediate drying may take place before the final baking, and is 
effected in iron boxes in a hot air chamber having a temperature of about 
150° F. 

The wood casings consist of cedar blocks, grooved to receive the leads, 
and measuring 7J" X 2J" X 3^". Each block is provided with six grooves 
and after insertion of the leads, the blocks are dipped in glue and clamped 
together in bundles of a dozen or less, and allowed to dry. Finally, the 
glued blocks are cut up into individual pencils, which are then trimmed, 
sandpapered, painted, varnished, and stamped. 

To impart the necessary strength, the softer grades of pencils have 
leads of greater diameter than the harder grades, in which the larger 
proportion of clay used serves the same purpose. 

Artificial graphite is not suitable for pencils, as it is apt to contain 
particles of carborundum. A small proportion of flake graphite enters 
into certain grades of pencils, but, as noted above, the bulk consists of the 
amorphous variety. 

A common proportion in pencil making is two parts of graphite to 
three of clay; while such other substances as sulphide of antimony, lamp 
black and finely divided metallic lead are sometimes incorporated into 
the mixture. The leads may also be boiled in wax or tallow, in order to 
remove grittiness or to render them tough. 

Practically all of the pencil graphite consumed on this continent comes 
from the Santa Maria mines near La Colorado, in central Sonora, Mexico, 
which are owned and operated by the United States Graphite Company, 
of Saginaw, Michigan. This graphite is wholly amorphous, and even 
under a high power microscope shows only shapeless particles. The 
deposits are the result of the metamorphism of coal seams by a granite 
intrusive. An analysis of run-of-mine ore showed 1 : — 

Carbon 86-75 

Silica .'. 7-60 

Iron oxide .' 0-65 

Alumina 5-00 



100 CO 



Graphite Mining in Mexico, issued by the United States Graphite Company, Saginaw, 
.. 1910. 



Mich., 1910 



148 

The above deposits contain sufficient graphite to meet the limited 
demand for pencil graphite for an indefinite period, and there is thus little 
likelihood of the amorphous graphite of the St. John, N.B., district 1 , or 
of other localities in New Brunswick and Nova Scotia, coming into request 
for the purpose. These are the only Canadian graphites so far known that 
might possibly be suitable for pencil manufacture, but, the graphite content 
of the ore being relatively low, (under 50 per cent), the material can hardly 
hope to compete with the Mexican or other high grade, amorphous graphites. 

There are, of course, a great many recipes for the composition of pencil 
lead, practically every manufacturer having his own formula. 

The proportions in which the clay and graphite are mixed depends 
largeh^ on the quality of these ingredients and the grade of pencil desired. 
Two parts by weight of graphite and three parts of clay, or even parts of 
both, are considered good proportions for ordinary pencils, but it is evident 
that a variety of hardnesses and degrees of marking pawer may be produced. 
The greater the amount of clay used, the harder and less lustrous will be 
the lead. 

The following 2 mixtures have been emplo3 r ed in pencil leads: — 

Graphite 30 parts 

Clay 9 " 

Stibnite (grey antimony) 9 " 

Tallow 1 " 

The graphite is first ground and washed, and then dried and burnt 
for several hours. The tallow is melted and added to the mixture, which 
is then worked up in a lead mill. After burning, the leads are immersed 
in boiling wax. 

For very hard drawing pencils, the following mixture is used : — 

Graphite 36 parts 

Clay 18 " 

Stibnite 8 " 

Lampblack 2 " 

The use of clay in pencil lead mixtures is governed by its property 
of hardening when heated, as well as by its plasticity; and as the degree 
of hardness is dependent upon the temperatures at which the leads are 
burnt, it is clear that temperature control plays a very important part 
in the securing of the various degrees of hardness desired. 

If burnt too quickly, springing or warping of the leads will result. Leads 
spoilt in this way cannot be ground up and reburnt, but are useless for any 
further purpose. The leads are usually packed in powdered carbon in 
the burning crucibles. 

Thorough washing or elutriation of the ground clay is very important, 
in order to avoid grittiness of the leads. 

The wood usually employed in pencils is southern red cedar, but for 
the cheaper grades such woods as pine and fir are sometimes used. The 
lead pencil industry in the United States, alone, in 1906, is stated to have 
consumed 110,000 tons or 7,300,000 cubic feet of wood. 

1 See p. 22. 

2 Cirkel, op. cit., p. 263. 



149 
FOUNDRY FACINGS. 

While the term " facings" in general usage is applied to the facing sand 
which forms a layer about an inch thick around the pattern, in the specific 
sense it relates to those materials which are used to give the skin of moulds 
a smooth finish, so that the castings peel freely and cleanly on cooling. 

While different materials are used for this purpose, including talc 
or soapstone, carborundum, and various forms of carbon, such as sea-coal, 
charcoal, coke, gas retort carbon, etc., graphite is the most important of 
the facing materials for mould surfaces, and large quantities are used in 
foundry work. Practically the only market for the low grade dust graphite 
from the refining mills, which contains between 40 and 60 per cent carbon, 
is the foundry facing trade. 

It should be noted that foundries do not, generally, manufacture their 
own facings, but procure them from foundry supply firms having speci- 
ally equipped plants for grinding, mixing, and otherwise treating the w T ide 
variety of material used in foundry work. 

The preparation of graphite for facings, apart from the preliminary 
drying and crushing that may be necessary when the raw material is 
crude ores, such as Korean, Mexican, etc., and which are not required in 
the case of mill dust, involves grinding in tube mills, the product from which 
is air floated. 

Inasmuch as graphite possesses no adhesive property, it is necessary 
to add a proper bonding constituent to it when used as a facing for mould 
surfaces. This binding material is, usually, of a clayey, refractory nature. 
The binder absorbs a certain amount of moisture from the mould, and this 
holds the facing in place; and when the clay is calcined by the molten metal, 
the facing is rendered somewhat porous, thus allowing the exit of moisture 
and occluded gases. Proper proportioning of the graphite and binder is 
important, since, if there is too much of the latter, peeling becomes difficult, 
and if too little, the graphite runs before the metal. 

Carbonaceous facings, such as graphite, coke, charcoal, etc., are com- 
monly termed blackings, in foundry parlance, in contrast to silica, talc, 
soapstone, etc., which are called mineral facings. 

In applying graphite to green sand moulds, it is usually dusted on 
and then slicked off with the tool, or else rubbed on with the hand and 
the excess blown away. It is also laid on with a fine brush, care being taken 
not to disturb the sand surface. 

For dry sand work, the graphite is applied wet, in the form of a wash, 
the liquid used being molasses water or some other solution containing 
vegetable substance possessing adhesive qualities, such as the waste liquor 
from pulp mills ("glutrin"). The graphite is usually mixed with fireclay, 
and a syrupy mixture is obtained which is applied with a swab. 

With regard to the grade of graphite best adapted for foundry facings, 
the best results are obtained by the use of high grade flake. This material 
may be adulterated considerably and yet be better than the poorer varieties 
of graphite. Soapstone, coke, anthracite, and even bituminous coal is 
often ground up with graphite in order to cheapen the mixture. The 
preparation of proper specifications, based upon reliable tests, is one of 
the urgent problems of the foundry 1 . 

In the manufacture of foundry facings, more graphite is utilized than 
in the making of any other article in common use, with the exception of 
crucibles. 



1 See R. Moldenke, Principles of Iron Founding, 1917, p. 305. 



150 
DRY BATTERIES. 

Graphite is employed extensively in dry batteries, where it serves 
to give conductivity to the mass of manganese dioxide. Formerly the 
amount of powdered carbon in a dry cell, amounting to nearly half the 
total solid ingredients, consisted largely of coke, retort carbon, petroleum 
coke, ground carbon rods and electrodes, etc., all of which are considerably 
cheaper than graphite of the required purity, though not of such good 
conductivity. 

According to Burgess and Hambuechen 1 , the following may .be taken 
as representing the filling mixture in well known types of dry cells : — 

Manganese dioxide 10 pounds 

Carbon or graphite, or both 10 " 

Sal ammoniac 2 " 

Zinc chloride 1 " 

Much of the variation found in dry batteries is due to varying quality 
of the carbon used in the filler, and the above-named writers consider that 
the u more recent improvement in dry cells is undoubtedly due largely 
to the liberal use of this highly conductive, though more costly, form of 
carbon." 

According to Dr. E. Acheson 2 , a very large percentage of the dry 
batteries, manufactured in the United States are filled with artificial 
graphite. 

Natural flake graphite is also used, and for this class of work the fine 
dust from graphite mills or other low grade concentrates may be cleaned 
and rendered suitable. Such low grade materials are cleaned with the aid 
of kerosene oil at Chester Springs, Pennsylvania, and a product claimed 
to be practically free of all impurities is secured and sold to dry battery 
makers. 3 

ELECTROTYPING GRAPHITE. 

Very finely powdered graphite is used in electro typing for two purposes: 

(1) The forms, after being made up, are dusted over with the graphite 
and placed in a machine and highly polished, this enabling them to strip 
clean and sharp from the wax mould. 

(2) The wax mould with the impression of the original is then dusted 
with graphite, which spreads freely and smoothly over the whole surface 
and into the fine interstices of the mould ; it is then polished and is ready for 
immersion in the copper bath. 

Natural amorphous, flake, and Ceylon graphite are all used for the 
above purpose. To ensure a uniformly polished and conducting surface, 
upon which the preliminary plating has instantaneous effect and upon 
which deposition of the copper proceeds immediately upon applying the 
electric current, without creeping and gradual covering, only the purest 
graphite should be used. 

W. Pfanhauser 4 gives the following details regarding the use of graphite 
in electro typing: — 

The use of graphite as a conducting coating for the forms was proposed by 
St- W. Wood, in 1873. Only the purest graphite is suitable, and several processes for 

1 Trans. Amer. Electrochem. Soc, Vol. XVI, 1909, p. 99. 

2 Paper read before the National Gas and Gasolene Engine Trades Association, 1910. 

3 It is probable that this material is employed largely, also, in the manufacture of high 
grade, lighting carbons. 

4 Die Galvanoplastik, Monographien iiber angewandte Elektrochemie, Vol. XI, 1904, p. 25. 



151 

cleaning graphite chemically for the above purpose have been patented. In consequence 
of its unctuous character, graphite adheres better to forms than the various metallic 
powders that have been suggested as substitutes, and forms polished with graphite have 
a smoother surface than those on which such powders are used. 

The graphite is shaken onto the forms and rubbed on with a fine camels hair brush, 
to which is given a rapid, rotating movement. A correctly graphitized surface should 
possess a lustrous, metallic black appearance, and great care must be taken to leave no 
portion of the form untouched by the brush, as this results in an imperfect deposition 
of the copper. A very soft brush is not essential; in fact a rather stiff bristle brush may 
be used for all except wax or gelatine moulds. It is advantageous, in the case of gutta 
percha forms, to breathe upon the surface before applying the graphite, as this results 
in better adhesion. 

On wood or plaster moulds, that are saturated with stearine, it is best to apply 
a paste of graphite and water. This is allowed to dry, and the superfluous graphite is 
then brushed off. 

Special machines for applying the graphite are used where large surfaces have to be 
covered, and these give much quicker and more even results than hand work. These 
machines consist essentially of a rotating horizontal plate on which the form is laid, and 
above which a wide brush moves with a rapid whirling movement. Large forms are 
coated in about 5 minutes with such a machine. Such a machine makes 300 revolutions 
and is fitted with a brush about 30 inches wide. 

GRAPHITE BRUSHES. 

While brushes for dynamo and motor commutators were formerly 
made of copper, such brushes have now been almost entirely superseded 
by carbon or graphite brushes. Graphite brushes are self lubricating, have 
long life and are of high conductivity as compared with carbon brushes. 
The graphite used may be the natural flake variety or Ceylon plumbago, 
but for direct current machines brushes of artificial graphite are also exten- 
sively used. 

According to the amount of current that the brushes are required to 
carry, the composition may be varied as under: — 
Graphite 

Graphite + petroleum coke 

Graphite + petroleum coke + powdered copper. 
The heavier types of brush may contain as much as 90 per cent of copper. 

The above materials 1 in a finely powdered state, together with coal 
tar, to serve as a binder, and benzol, are thoroughly incorporated in a steam 
jacketed mixer. The hot material from the mixer is then placed in steel 
forms and moulded in a hydraulic press under a pressure of 10-20 tons per 
square inch into slabs of varying thickness but of more or less uniform 
surface (3X5 inches). These slabs are then packed into saggers with 
powdered coke and are baked at a temperature of 1300°C for about 8 
hours. The total time of remaining in the kilns is 3J days. 

The baked slabs are then cut into the required sizes by carborundum 
saws and smoothed. They are then bored and countersunk for the pigtail 
attachment. Certain types of brushes have their upper ends and pigtail 
socket electroplated with copper, and others are tinned by dipping the 
copperplated brush into a bath of molten tin. This is done to ensure a 
perfect contact between pigtail and brush. 

The pigtail is attached to the brush either by soldering it into a hole 
bored for the purpose or by riveting it onto the brush. 

The Morgan Crucible Company, of London, make graphite brushes 
which are constructed in layers, in such a way that the resistance across 
the brush is from seven to eight times that in the opposite direction. In 

1 Information courteously supplied by the United States Graphite Company, Saginaw, Mich. 
67945—11 



152 

this way, a path of high conductivity is provided for the current into the 
external circuit while the cross resistance of the brush tends to reduce the 
current in the short circuited coil. The brushes made by this Company 
are of a composition known as Morganite, which consists of Ceylon or 
flake graphite ground to 100 mesh and moulded under a pressure of 20 
tons per square inch. 

Metal brushes are objectionable for several reasons, chief of which are 
that it is difficult to keep the surface of the commutators smooth, since 
the soft copper bars and the soft metal brushes do not wear well, and there 
is always a tendency for soft metals to become rough when rubbed together. 
The tendency of a dynamo to spark at the brushes, also, is greatly lessened 
by using brushes made of comparatively high resistance material, such as 
carbon or graphite, in place of low resistance material like metal. 

The following notes on the manufacture and composition of graphite 
brushes are taken from an article by Warren C. Kalb, in " Power," Feb- 
ruary 18, 1919, p. 241:— 

The carbon-graphite brush is the type usually spoken of as an ordinary carbon 
brush. It is composed principally of amorphous carbon, usually in the form of coke, 
to which is added sufficient graphite to give the brush some lubricating property and 
increase its conductivity to some extent. Natural graphite is generally used for this 
purpose, and as this usually contains a considerable percentage of foreign material of more 
or less abrasive nature, brushes of this class as a rule are abrasive to an appreciable degree. 

The practice is quite common among both manufacturers and users to impregnate 
brushes of this class with some lubricating material. This not only tempers the abrasive 
characteristic of the brush and reduces its friction, but improves the commutating property 
as well, due to the higher contact resistance created by the film of lubricating material, 
which forms at the brush face. 

The disadvantages of this treatment are that it is driven off when the brush encounters 
conditions of high temperature. It has a tendency to collect dust from the atmosphere, 
and if this happens to be of an abrasive nature, as is the case around cement mills and 
similar service, the commutator wear resulting from this cause may be quite severe. 
Finally, brushes with lubricating treatment have a much greater tendency than others 
to collect copper on the face of the brushes. 

Most brushes of the carbon-graphite class are within the medium range of hardness. 
They are not adapted to undercut mica, due to their abrasiveness and the artificial lubrica- 
tion they generally require. Most grades of this class are of low carrying capacity and 
are not adapted to high peripheral speed. However, this type of brush will take care of a 
wide range of operating conditions within the limits of its characteristics and, considering 
its moderate price, must be classed as a good all-around brush. 

There is another class of brushes in which a considerable or even the predominating 
percentage of the composition is graphite, the remainder being coke or some other form 
of amorphous carbon. These are known as graphite-carbon brushes. A great many 
grades of brushes fall within this class, so that the class as a whole covers a very large 
field of application, although the individual grades may not apply to such a broad range of 
service. 

Brushes in this class usually contain sufficient graphite for lubrication, so that 
lubricating treatment is seldom used. Artificial as well as natural graphites are used, 
depending on the characteristics that it is desired to incorporate in the brush, and the 
abrasive properties will depend upon the graphite that is selected. Some brushes within 
this class possess very little abrasive action, while there are others possessing considerable. 
In point of hardness these brushes will range from soft to medium hard. The carrying 
capacity will usually be higher than the grades in the carbon-graphite class, but the contact 
drop of most of these brushes is medium or low unless a lubricating treatment is used. 

Brushes of this type find an extensive application on industrial motors, moderate- 
speed generators, mining and mill service, and railway motors. Certain grades of this 
type are especially well adapted to fan motors, magnetos and other small machines both 
of the direct current and universal types. Some excellent grades of moderate priced 
brushes will be found among the various makes of graphite-carbon brushes. 

There are numerous grades of brushes on the market composed entirely of graphite 
except for the binding material necessary to hold the particles of graphite together. These 



153 

are characterized by high carrying capacity, medium contact drop and low coefficient 
of friction, adapting them especially to high commutator speeds. 

There are a few grades of graphite brushes on the market manufactured by special 
methods that give the material a very high resistance and a somewhat improved com- 
mutating characteristic over the ordinary type of graphite brush. These grades, however, 
have a rather limited field of application. There are also grades possessing very low 
specific gravity. These are manufactured in this way to reduce the inertia of the brush 
as much as possible, adapting it to very high rotative speeds. 

Most brushes in the graphite class are non-abrasive or at most but slightly abrasive 
and should generally be used on commutators of which the mica is undercut. A few of the 
slightly abrasive grades can be used on unslotted commutators where conditions are not 
severe. All the brushes in this class are soft, some of them being very soft. They possess 
low mechanical strength, so are incapable of meeting severe mechanical conditions and 
should be operated at low spring pressure. Where quietness of operation is an essential 
characteristic, this type of brush has much in its favour. Classes of service in which 
they are used to a considerable extent are as follows: Turbo-generators and other high- 
speed types, automobile fighting generators, electric vehicle and battery locomotive 
motors, battery charging and other low voltage generators, slip rings and occasionally 
as lubricating brushes on electro-plating generators. 

Electrographitic Brushes. 

Perhaps the highest stage in the development of carbon brush manufacture up to 
the present time has been reached in the electrographitic brush. This type is made up in 
the first place of certain forms of amorphous carbon carefully selected to give the desired 
characteristics to the finished product. In the final baking operation it is carried to an 
extremely high temperature, which results in a modification of the material composing 
the brush, leaving all or part of it in the form of graphite. It is possible to make this 
type as near absolutely nonabrasive as any brush can be made. It is also manufactured 
with varying degrees of abrasiveness to meet special requirements. 

In relation to other types of brushes this class is hard and some grades are extremely 
so; still, owing to its dense structure high conductivity is attained. Mechanical strength 
and toughness are pronounced characteristics of nearly all grades. The commutating 
properties of brushes of this class are above the average, and by proper selection of raw 
materials it is possible to secure a very high contact drop without the use of any impregnat- 
ing treatment. This high contact drop, combined with the high conductivity and low 
coefficient of friction, gives an ideal combination of brush characteristics, making certain 
grades applicable to a very wide field of service. 

Electrographitic brushes have been used on practically every conceivable application 
except electroplating generators, and even on these the more graphitic grades are sometimes 
used for lubrication. The non-abrasive grades are especially well adapted for use on 
undercut commutators, the hardness of the brush giving a cleaning action, which polishes 
the surface of the commutator well without causing any wear. For use on collector 
rings the electrographitic brush is well adapted wherever mechanical conditions are severe, 
due to its greater ruggedness. 

These brushes may be used up to current densities as high as 80 amperes per square 
inch on the alternating current rings of rotary converters, and occasional instances of 
successful application at even higher current densities have been noted. 

Trend in the Use of Brushes. 

The trend of development at the present time seems to be away from the use of 
metal-graphite brushes on slip rings and toward the use of graphite and electrographitic 
brushes at current densities that are suited to these grades. There are many things to be 
said in favour of this tendency on all classes of alternating current machines. However, 
a serious objection is met with on induction motors of the slip ring type where it is desired 
to keep the slip at as low a figure as possible. Here the higher contact drop of graphite 
and electrographitic brushes will result in a greater percentage of slip than will be experi- 
enced with metal-graphite brushes. 

For certain classes of service a brush is required having a contact drop much lower 
than that possessed by any carbon brush, yet above that of pure metal. For this purpose 
brushes are manufactured of a composition made up of graphite and metal powder. 
Copper powder is used in some grades. However, pure copper powder does not make the 
best brush for use on slip rings, owing to its tendency to cut the rings. For this reason 
it is customary to alloy the copper to some extent with tin, zinc, lead, or some*other metal 
67945—1H 



154 

making a brush that is much less liable to score the rings. Copper, however, remains 
the predominant element in the composition. 

The materials are thoroughly mixed in the desired proportions with a binding 
material to hold the metal and graphite particles together. It is then molded at high 
pressure, after which it is baked to carbonize the binder. In some grades the binding 
material is omitted and the temperature carried to a point of partial fusion of the metal, 
so that the material is bound together into a compact mass without the use of any addi- 
tional binding agent. In addition to raising the contact drop somewhat above that of the 
pure metal, thus making it possible to secure good commutation on machines of low voltage, 
the graphite has another function — that of lubrication. Where properly applied these 
brushes can be used on commutators and slip rings at a fairly high peripheral speed without 
difficulty being encountered. 

GRAPHITE ELECTRODES. 

Electrodes were formerly made of powdered petroleum coke, mixed 
with tar as a binder. This mixture was moulded under pressure and baked 
at a bright red heat, when the tar is carbonized. At this stage the process 
stopped. The first stage in the manufacture of graphite electrodes is 
essentially the same as described above. Anthracite coal is largely used to 
replace the petroleum coke, and provided it is clean, gives good results. 
Hand picking or some other method of cleaning should be resorted to in 
the case of coal containing much slate or other foreign substance. The 
carbon rods, made as above, are now placed in an electric furnace and 
converted into graphite at a temperature of about 7500°F. (see page 116). 

Graphite electrodes possess an electrical conductivity four times that 
of carbon rods. They can, also, be shaped, threaded or planed, whereas 
the carbon rods cannot be so worked : they can thus be tapped and threaded 
and fed into the furnace as a continuous rod, whereas, as soon as the 
carbon rods have been partly consumed, the outer connexions can no longer 
withstand the high temperatures produced and about half the electrode 
has to be thrown away. 

It has not been found satisfactory to make an electrode out of powder- 
ed graphite mixed with some sort of binder, as no plastic form of graphite 
possessing the requisite bonding properties is known. In place of the 
latter, some form of hydrocarbon bonding agent must be used, and these 
do riot possess the necessary strength and soon break down, especially 
when the electrodes are used in electrolytic work. « 

The tensile strength of graphite electrodes is about 20 per cent less 
than that of ordinary carbon electrodes and they are much softer. 

In the forming of carbon electrodes, previous to graphitizing,two methods 
are used. They can either be placed in a mould and formed under pressure, . 
or they can be extruded through a die. For electrolytic work, extruded 
electrodes have been shown to be superior to the moulded ones, being more 
homogeneous and of lower porosity, and most of the Acheson graphitized 
carbon electrodes are made by the extrusion method. 

Since graphitized carbon rods are so readily machined, many small 
articles such as discs, bushings, washers, etc., can be made from solid rods 
far more satisfactorily than by moulding. Graphite moulds, made from 
solid blocks, have also been used with success in casting the precious metals, 
as well as in the glass industry. 

High grade arc carbons (electrodes) for use in searchlights, moving 
picture lanterns, etc., are made from specially refined natural graphite. 
(See footnote, p. 150.) 



155 



GRAPHITE FOR LUBRICATING. 



Graphite possesses a very low coefficient of friction, a property that it 
retains under practically all working conditions. In addition, it is soft 
and readily adheres to metallic surfaces under light pressure, filling up 
the pores in the metal and smoothing the microscopic roughness of the 
surfaces in rubbing contact. The surfaces thus coated are covered with a 
veneer of graphite which reduces their coefficient of friction to practically 
that of graphite itself and also serves to protect them from the action of 
corrosive solution or vapours. This applies especially to cylinder lubri- 
cation, where high pressure steam, oil or gas is used. Under such condi- 
tions, oil and grease lubricants tend to lose body or to char or vapourize 
under the action of the heat and vapour to which they are exposed, and 
graphite has now largely supplanted lubricants of the above nature for 
cylinder lubrication. 

In heavy bearings, also, grease and oil tend to squeeze out from 
between the surfaces, with the result that the metal parts touch. Graphite, 
on the other hand, forms a veneer or coating on both bearing surfaces, 
so that a graphite-graphite contact instead of a metal-metal contact is 
secured. 

Of other natural lubricants, talc and mica may be mentioned, but 
neither of these is adapted for work under severe conditions to anything 
like the extent that graphite is. 




DRAIN 



HEX. NUT 
$■" PIPE THREADS 
fe" BRASS PLUG 

Fig. 42. Type of automatic graphite lubricator (United States Graphite Company, 

Saginaw, Mich.) 

For ordinary lubricating purposes in loose, open bearings, gears, slides, 
etc, graphite is commonly mixed with oil or grease, and there are a variety 
of such compounds on the market, many of them designed for work under 
special conditions, such as exposure to salt water, acids or alkalies, in 
dredges, pump plungers, winches, mining machinery, etc., or at different 
temperatures, where varying degrees of viscosity are required. 



156 

In cylinder lubrication for steam and gas engines, compressors, etc., 
modern practice is to feed dry, flake or powdered graphite in addition to 
grease or oil. For this purpose, numerous special lubricators have been 
devised, one of which is shown in Fig. 42. In marine engines, the use of 
graphite for cylinder lubrication is especially advantageous, as by its use, 
the amount of oil finding its way into the condensers and boilers is mater- 
ially reduced. 

Graphite is also used in pipe joint compounds, for lubricating and 
sealing the threads and flanges of steam, water, gas, oil and air pipes, and 
for bolts, nuts, studs, caps, boiler plugs, manhole plates of boilers, gas 
retort doors, metal gaskets, etc. Such compounds replace, and are claimed 
to be superior to, red or white lead. As in the case of graphite paints, 
superior merit is claimed for each of the three types of graphite — artificial, 
natural flake, and natural amorphous — for use in lubricating oils and 
greases. 

It is claimed for the amorphous and artificial graphites that they are 
both purer and more capable of being reduced to an impalpable powder, 
that will remain in suspension in oil, than the natural flake graphite, for 
which reasons they are to be preferred. The matter of the suspension of 
graphite in oil (with special reference to lubricating oils) has been consider- 
ed by C. H. Bierbaum, in a paper read before the American Society of 
Mechanical Engineers 1 . 

The following abstract of this paper is of interest : — 

From a purely mechanical viewpoint, the suspension of graphite in oil should be a 
relatively simple matter; unfortunately, however, when the particles of graphite are fine 
enough to be able to defy the force of gravity, they are then subject to another force 
known as the Brownian movements. Under the latter force the graphite particles are 
subject to what approaches perpetual motion; it is not a continued movement in one 
direction, but a zigzag course, caused by the free electrons striking the particles of 
graphite. A particle on being struck starts with a jerky movement and continues moving 
until arrested by the fluid friction of the oil, provided it has not already been struck by 
another electron causing it to bound off in another direction. An observer who saw this 
fascinating action for the first time expressed himself to the effect that the particles seemed 
to be on a St. Vitus dance. During these erratic movements the particles of graphite 
collide with each other, and as a result adhere; they in turn are struck by other particles, 
and in this manner there is gradually built up a mass of adhering particles which is subject 
to the action of gravity and results in settling out. It is obvious that the greater the 
number of free electrons present in the oil, the more rapidly the coagulation and settling out 
process should proceed, and such is the case. It is fully borne out by experience that the 
addition of a free acid or salt greatly accelerates the precipitation; in fact, any electrolyte 
present has this effect, such as the acid residue or its resultant neutralized salt remaining 
in a lubricating oil after refining, or the rancidity of an oil, all tending to increase the 
number of free electrons and the precipitation of the fine particles of graphite. 

Various expedients have been resorted to in order to effect so called permanent 
suspension of graphite in oil. The one most commonly made use of is; hat of coating 
the finely ground particles with a foreign substance and then effecting a high dispersion 
of these coated particles throughout the oil. The coating material is usually a vegetable 
compound; if an oil it should be one insoluble in the mineral oils, such as castor oil, or it 
may be tannic acid or an allied tannin compound. 

The value of a so-called permanent suspension of graphite in oil is more fanciful 
than real, for the reason that in all such attempts the graphite is ground to such an 
extreme degree of fineness that this very fineness mitigates against its being useful. In a 
bearing properly constructed, lubricated and in operation, the bearing surfaces are com- 
pletely separated by the oil film and the extremely fine particles of graphite simply float 
in the film, exerting no appreciable effect either beneficial or otherwise. 

The time, however, when graphite can be of benefit and perform its only and supreme 
function is when the oil film between the bearing surfaces is destroyed and the graphite 
serves as a solid lubricant. The graphite is carried between the bearing surfaces by the 

1 See Iron and Coal Trades Review, January 1918, p. 718. 



157 

oil, and in the same manner, when the oil film is destroyed by being squeezed out, the 
graphite particles are carried along with the oil from between the bearing surfaces until 
the film is reduced to a thickness corresponding to the dimensions of the largest particles 
of graphite which at this stage will be arrested and held between the surfaces. Upon the 
complete destruction of the film, these particles so held are crushed and embedded into 
the grain and pores of the surfaces, and thus are made to perform their function of solid 
lubrication. It is evident that the smaller the particles are, the less will be the amount 
of graphite so intercepted between the bearing surfaces; therefore, a given amount of 
graphite is most efficient if it exists in particles of the largest possible size. The more 
nearly permanent a graphite suspension is, the more nearly does it approach the colloidal 
state and the more completely is it carried out from between the bearing surfaces when 
the oil film is being destroyed. 

te$ This can be demonstrated in a most striking manner by taking a light coloured 
lubricating oil, thoroughly mixing with it a definite amount of graphite, and then placing 
it between two highly accurate glass surfaces and observing the amount of colour left 
after a definite pressure has been applied for a definite time, while maintaining a fixed 
temperature. An amorphous natural graphite, ground so that its coarsest particles did 
not exceed 0-0002 in., showed under the foregoing conditions an almost opaque surface, 
while a commercial graphite suspended in tannin, and whose largest particles did not exceed 
1-250,000 in., showed a substantially colourless surface. This is readily accounted for 
by the fact that the largest particles in the one graphite contained 125,000 times the bulk 
of those in the other, a condition existing at the time the glass surfaces in each case had 
approached each other near enough to arrest the flow of the respective particles. 

The carbon content of graphite is not an indication of its lubricating value or its 
purity, for the reason that the percentage of amorphous carbon in some varieties is 
comparatively high. Amorphous carbon, or carbon not completely graphitised, can best 
be classed as an inert impurity; its presence always shows extreme blackness. The same 
is true of another common impurity, hydrogen, as a hydrocarbon; this is also black, 
whereas the purest graphite is a dark steel-grey when mixed with a clear white oil. The 
chemical laboratory can only give valuable information on the subject of the graphites 
when the work is done by an expert or specialist. i dj_;y ,j ig* ggi , 

Dry graphite powder is used for lubricating the actions and bridges 
of pianos and organs, and in short, any wooden or other surface when the 
use of oil or grease might be detrimental, such as in textile machines. It 
is employed, also, in type-setting machines, to give the space bands, 
channel plates, etc., a dry, smooth surface. 

To minimize water friction, yacht and launch bottoms are sometimes 
dusted with graphite, after a preliminary light coat of varnish or shellac 
has been applied, and when dry, are polished with cloths or waste. The 
graphite used for this purpose is sometimes termed potlead. 

For the lubrication of bearings and bushings that are difficult or 
impossible of access, the Bound Brook Oilless Bearing Company, Bound 
Brook, New Jersey, make specially designed, self-lubricating devices. One 
type (Nigrum bearings) consists of ironwood, impregnated with a special 
lubricating compound containing graphite. Such bushings are used 
extensively for light duty parts in automobiles, such as for shackle pins, 
spring eyes, etc. Saddles of spinning frames and roll holders in grinding 
mills of all descriptions may also with advantage be made of such impreg- 
nated wood; and it is also recommended for friction clutches and loose 
pulleys, and for use in the bearings of printing presses, paper, textile and 
winding machines. 

Some types of Nigrum bearings are illustrated in Plate LV. 

The same firm also make what is known as the Bound Brook bearing. 
This is a bronze bearing, cast with grooves or holes, into which a special 
mixture containing graphite is forced. After this lubricating material 
has been inserted, the bearings are baked for some hours, and are then 
broached. Some of the uses for which such self -lubricating bearings are 
especially adapted are trolley wheel and windmill bushings, clutch release 



158 

shoes, gas engine and starting motor bushings, etc. Several types of these 
oilless bearings are illustrated in Plate LVI. The graphite used in the 
manufacture of the above is a finely ground, natural flake, that is air floated 
to remove all trace of grit. 

Attempts have been made to produce a self -lubricating metal by intro- 
ducing graphite into the metal while the latter is in a molten state, but this 
procedure does not appear to have met with success. 

Such an antifriction alloy has been proposed by E. C. Miller, and 
consists of lead, antimony, tin, bismuth, and graphite. The individual 
metals are all melted separately. The lead and antimony are then mixed 
together, and to them the graphite is added, after which the tin and bismuth 
are inserted. The proportions in which the above ingredients are to be 
mixed are given as: — 



Lead 

Antimony . 

Tin 

Bismuth.. . 
Graphite . . 



36 parts. 
7 " 
2J " 



i " 

TO 
1 " 

4 



The Morgan Crucible Company, of London, make bearings and bush- 
ings machined out of solid Morganite, a special graphite material made 
by the Company. These bearings are claimed to be mechanically strong, 
and being composed entirely of self lubricating material, to possess practi- 
cally the lowest possible coefficient of friction. 

The Acheson Graphite Company, of Niagara Falls, use so called 
"deflocculated graphite" in their Oildag lubricating compound. This 
deflocculated graphite is claimed to be "graphite reduced to the molecular 
form, the finest possible state of subdivision". It is so finely divided that 
"when diffused in water, it will run with the water through the finest filter 
paper". Such graphite is prepared from artificial graphite, made in the 
electric furnace, which is first ground very fine and airfloated. This air- 
floated graphite is termed disintegrated graphite, and from it the defloc- 
culated graphite is prepared by a process involving the addition of tannic 
acid. According to Spear 1 , on masticating artificial graphite with gallo- 
tannic acid, stable solutions of colloided graphite containing as much as 
1 per cent of graphite can be obtained. In order to produce an oil sus- 
pension, it is first necessary to make a paste of graphite and tannin in 
water, oil being gradually substituted for the water during the mastication 
and the oil paste diluted to the desired consistency. The graphite particles 
may be precipitated out of solution by the action of acids. 

GRAPHITE PAINTS. 

Graphite is used extensively as the pigment in paints that are called 
upon to withstand the corroding attack of sulphurous gases, acids, alkalies, 
etc. It is considered especially valuable in paints for metal and other 
roofs in a smoke laden atmosphere, tanks, pipes, trestle work, boiler fronts, 
smoke stacks, standpipes, gasometers, steel railroad cars, bridges, etc. 

There is a diversity of opinion as to the most suitable kind of graphite 
for graphite paints, and the natural amorphous, natural flake and artificial 
varieties are all employed by different manufacturers. (See under 
Lubricants). 

1 The Chemistry of Colloids, Zsigmondy and Spear, 1917, p. 266. 



159 

The following remarks on the subject of graphite paints are taken 
from "The Chemistry and Technology of Paints/' by M. Toch, second 
edition, 1916, p. 101, Van Nostrand Company, New York: — 

The purer a paint pigment is as to its content of carbon the poorer is the paint pro- 
duced. If graphite be taken with a content of 80 or 90 per cent carbon and mixed with 
linseed oil, it forms a porous, fluffy film, and the particles of graphite coagulate in the lin- 
seed oil and produce a very unsatisfactory covering. If graphite be diluted with a 
heavier base, its weakness then becomes its strength and a very good paint is formed. 
Many of the characteristic chemical and physical defects of red lead are largely reduced and 
frequently eliminated when it is mixed in proper proportion with graphite, a high grade 
of graphite when finely ground with linseed oil acting as a lubricant and sliding under 
the brush. 

Pure graphite paint, as is well known, will cover from 1,000 to 1,600 square feet to the 
gallon. Such a paint film is so exceedingly thin that, while it looks good to the eye, in a 
short period decomposition more easily takes place beneath it than beneath many poorer 
paints. It is therefore essential to reduce graphite with a heavier base, and to this end 
it has been found that a mixture of silica and graphite produces very good results; but 
even this paint has the objection of having too much spreading power. 

Misnomers have crept into the paint trade in regard to graphite paints, such names 
as green graphite, red graphite, brown graphite, etc., being in use, when in reality such 
graphites do not exist, excepting as far as graphite has been mixed with pigments of these 
colours. 

A six year test of a linseed oil paint made with a neutral ferric oxide, containing 
in its composition 75 per cent ferric oxide and 20 per cent silica mixed with graphite con- 
taining 85 per cent graphitic carbon, has proved itself to be as good a paint as can be 
desired for ordinary purposes. The pigment in a paint of this kind will withstand the 
chemical action of gases and fumes, but the oil vehicle is its weakest part. 

Since the electro-chemical industry has been developed at Niagara Falls graphite 
has been made artificially and is sold under the name of Acheson Graphite. This graphite 
is to be commended as a paint material on account of its uniformity and fineness of grain, 
but it should not be used alone as a pigment, for as such it possesses the physical defect 
of lightness just described. A graphite paint containing more than 60 per cent graphite 
does not serve its purpose very well unless 40 per cent of heavy pigment is added, such as a 
lead or a zinc compound. A rather unfortunate defect in the graphite paints containing 
a large amount of graphite is the smooth and satin-like condition of the paint film, which 
is poorly adapted for repainting. It has often been noted that a good slow drying linseed 
oil paint will curl up when applied over certain graphite paints, because it does not adhere 
to the graphite film. On the other hand, if particular forms of calcium carbonate, silica, 
or ferric oxide are added to graphite, a surface is presented which has a tooth, to which 
succeeding films adhere very well. 



STOVE POLISH. 

For stove polish, an amorphous natural graphite is usually employed, 
which is worked up into the form of a paste, cream, cake, powder or liquid, 
with the addition of a clay, rosin, asphaltum or soap binder in the case of 
the solid polishes, and of a gasoline or water vehicle for the liquid kinds. 

Both Korean and Mexican graphite are suitable for this class of work. 
A high degree of purity is not essential, and the addition of carbon black, 
prepared by condensing the products of combustion of natural gas, is 
sometimes made to intensify colour. The graphite used in all the forms 
of polish is ground to an impalpable powder, and in the case of cake polishes, 
the graphite and clay are first moulded or poured into the desired shapes 
and then baked. 

Donath 1 , gives the following as the constituents of a liquid stove 
polish: benzine, 30 parts; graphite, 30; cocoanut oil and palm oil, J; 
dilute ammonia, 30; oak bark, 1; oxide and sulphate of iron, §. 



Op. cit., p. 131. 



160 

BOILER GRAPHITE. 

In recent years, tbe use of graphite in boilers, for preventing scale, 
has been widely advocated. Boiler scale greatly lowers the conductivity 
of the boiler heating surfaces. Scale also prevents the cooling action of 
the water from protecting the metal against burning, and in consequence, 
the plates are liable to become so overheated as to bag or crack. 

The action of graphite in the elimination of boiler scale is purely 
mechanical, and is not affected in any degree by acidity or alkalinity of 
the water or by heat. Small particles of graphite simply work their way 
through the minute fissures existing in old scale, and gradually penetrate 
between the scale and the metal, loosening the former so that it may be 
readily rapped off or removed with regular cleaning tools. Even a thick 
accumulation of old scale may be removed in this way, but a period of 
several months may be required to completely loosen it. If the use of 
graphite is adopted when a boiler first comes into use, any great accumu- 
lation of hard scale may be effectually prevented, as the particles become 
incorporated with the scale as it forms, rendering it soft and friable, in 
which form it may readily be removed with a minimum of labour. 

The graphite usually recommended for the above purpose is a very 
finely ground flake, though the amorphous and artificial varieties also are 
used. 

The amount of graphite recommended to be used in average practice 
is two-fifths of a pint for a boiler up to 100 H.P., with an additional one- 
fifth of a pint for each 50 H.P, rise. One pint of ordinary flake boiler 
graphite weighs about half a pound. The most satisfactory results are 
obtained by the regular introduction of small amounts of graphite, but it 
is also recommended to put about two quarts into a boiler after cleaning. 

The graphite may be conveniently introduced into the boiler by mixing 
it with hot water and feeding through the pump suction after blowing down 
about two gauges. 

For locomotives, about one pound (one quart) of graphite per day is 
considered sufficient for ordinary engines, and two pounds for the large 
types. A simple method of introducing the graphite in this case is to 
place it directly in the tank. 

GRAPHITE FOR POWDER GLAZING AND SHOT POLISHING 

Graphite is employed for giving a protective finish to powder grains, 
in order to protect them from damage by moisture. It is also used to give 
a polish to shot. 

SUBSIDIARY USES. 

Minor uses to which graphite is put are in engine packing, hard rubber 
compositions, cord and twine manufacture, hat polishing, and in the 
manufacture of wire ropes and cables. 

It is also employed in rubber valve discs and washers for steam and 
hot water connexions, in sheet packing for steam joints and as a coating 
on piston ring packing. 

In addition to being used to polish and coat black powder grains in 
order to protect them from moisture, graphite is similarly employed in 
connexion with smokeless powder 1 , for the purpose of avoiding difference 
of potential with consequent danger of sparking between the grains. 

1 Haenig, Der Graphit, p. 150. 



161 

According to Donath, graphite is mixed to the extent of 25 per cent 
with gelatinized nitro-cellulose, in order to reduce its destructive effect 
on the weapons in which it is used 1 . 

Graphite also has found application in the manufacture of certain 
kinds of carbon paper. 

According to Miller 2 , amorphous graphite is sometimes employed as 
a filler in fertilizers, where it serves to coat the particle and prevent the 
absorption of moisture, with consequent caking; also, to colour and glaze 
tea leaves and coffee beans, and in printer's ink and dyes for felt hats. 

What are known as graphite slabs are used in flattening window glass. 
They must not be sensitive to sudden changes of temperature and must 
have great mechanical strength. They are satisfactorily made 3 from a 
coarse-grained material, but are surfaced with finer material. A common 
mixture for these slabs is: — 



Fireclay 1 part] f 2 parts 

Grog 1 

Graphite 2 



Grog . 1 \ or j 2 



The above materials are mixed dry, screened and pugged into a stiff 
paste. This paste is then allowed to sour for a few days and is again 
pugged and soured on alternate days for about a fortnight. The slabs 
are moulded in a wooden frame, the working surface being made with fine 
clay. The latter is usually placed in the bottom of the mould, which is 
then filled in with the coarser material. The slabs are afterwards polished 
successively with wet sand, finely ground grog and pumice stone or 
talc, friction being applied by a sandstone block held in a double handled 
frame. 

Graphite is sometimes added to the material used in making magnesia 
bricks, and its use increases the facility with which the material can be 
moulded, as well as increasing the heat conductivity of the bricks. 

In European practice, the graphite of old crucibles is often recovered. 
The pots are first carefully cleaned of slag and other impurities, crushed to 
powder and the graphite recovered by some form of separator, such as a 
vanner. Provided that the material is crushed fine enough, by using an 
air separator a fairly fine graphite is obtained, as well as a useful grog. 

1 The percentage of graphite given seems high enough to seriously reduce the propelling power 
of the explosive, and the writer has been unable to find corroboration of this alleged use of graphite 
in explosive manufacture. Donath quotes von Romocky, History of Explosives, Vol. II, p. 173, 
as authority for the above use of graphite. 

2 Report No. 6, Topographic and Geologic Survey Commission of Pennsylvania, 1912, p. 38. 

3 See A. B. Searle, Refractory Materials, p. 274. 



162 



CHAPTER VIII. 



THE CANADIAN GRAPHITE INDUSTRY. 

Production, Exports, Imports, etc. 

The production of graphite in Canada in 1918 was 3,114 tons. The 
above figure includes the three standard mill products — No. 1 and No. 2 
flake, and dust — ore shipped crude, and a small quantity of crystalline 
graphite or plumbago. The 1918 output was considerably lower than 
that of the previous year (3,714 tons), and the relative value was very 
much lower. About one-third of the total of 3,114 tons was crude shipping 
ore. 

As shown in the following table, the 1916 production was the largest 
in the history of the industry, but the value of the smaller 1917 output was 
considerably greater. 

Annual Production of Graphite in Canada, 1886- 1918. l 



Calendar Year. 



1886 


500 


1887 


300 


1888 


150 


1889 


242 


1890 


175 


1891 


260 


1892 


167 


1893 


Nil. 


1894 (a) 


3 


1895 


220 


1896 


139 


1897 


436 


1898....'. 




1899... 


1,130 


1900". 


1,922 


1901 


2,210 


1902 


1,095 



Tons. 



Value. 



$ 4,000 

2,400 

1,200 

3,160 

5,200 

1,560 

3,763 

Nil. 

223 

6,150 

9,455 

16,240 

13,698 

24, 179 

31,040 

38,780 

28,300 



Calendar Year. 


Tons. 


Value. 


1903 

1904 


728 

452 

541 

387 

579 

251 

864 

1,392 

1,269 

2,060 

2,162 

1,647 

2,635 

3,955 

3,714 

3,114 


$ 23,745 
11,760 


1905 


16,735 


1906 


18,300 


1907 


16,000 


1908 


5,565 


1909 


47,800 


1910 


74,087 


1911 


69,576 


1912 


117,122 


1913 


90,282 


1914 


107,203 


1915 


124,223 


1916 


325,362 


1917 


402,892 


1918 


248,970 







(a) Exports. 

No amorphous graphite has been produced in Canada for a number 
of years, the New Brunswick deposits having been abandoned in 1908. 
(See page 23). 

The price of Canadian flake graphite of crucible grade almost doubled 
during the war, attaining a maximum of 16 cents per pound in 1917. The 
prices of No. 1 flake, from 1914, to date, are shown below. These figures 
are for graphite consigned to the United States : — 

Prices of Canadian flake graphite, f. o. b., mills, 1914-19. 



1914 
1915. 
1916. 
1917. 
1918 



9 

13 
15 



7 
9 
12 
16 
16 
12 



cents per pound. 



1919 (February) 10 - 

From returns furnished to the Mines Branch, Division of Mineral Resources and Statistics. 



163 

As a war measure, the exportation of crucible grades of graphite from 
Canada was prohibited on November 7, 1914, to all foreign countries 
except France, Russia, Spain, and Portugal. On November 28, the prohibi- 
tion was made absolute, but on December 10 was modified to the extent 
of permitting export to the United States under license from the Minister 
of Customs. The above restriction remained in force all through the war 
period. 

In the following tables are shown statistics of exports and imports of 
graphite from and into Canada from 1910 to 1918, as well as the imports 
into Great Britain and the United States, 1914-1917. 

In connexion with the Canadian export figures it should be noted that 
the classification as required by the Tariff Act is somewhat obscure. The 
material included under "Crude ore and concentrates" consists, mainly, 
of crude ore, the product of a single mine, whose ore is sufficiently rich to 
be employed for certain purposes (foundry facings and the like) without 
being subjected to any cleaning process. The nature of this material is, 
perhaps, sufficiently obvious from the low value — 2 to 3 cents per pound. 
There are no exports of graphite concentrates, all concentrates being further 
refined at the mills to a finished product. The term " Manufactures " in- 
cludes refined graphite, i.e. the finished product of the mills, as well as articles 
manufactured wholly or in part of graphite. Canada, however, would 
appear to export little if any of such graphite manufactures, and the bulk 
of the values quoted probably relates to refined flake graphite. 

With regard to the imports classification, " Plumbago, not ground " 
probably may be taken as comprising chiefly Ceylon graphite for crucibles 
■or other purposes; while "Ground and manufactures" includes, variously, 
refined flake^ amorphous graphite, low grade foundry facing material, 
and articles composed wholly or in part of graphite (crucibles excepted). 

The import duty on graphite and graphite products into Canada is 
as follows: — 





Source. 




British. 


Foreign. 


Plumbago, not ground or otherwise manufactured. 

Plumbago, ground and manufactures of 

Graphite crucibles 


5 per cent 
15 per cent 
Free 


10 per cent 
25 per cent 







In addition, a war tax is levied on all the above; this amounts to 5 
per cent in the case of British shipments and 7§ per cent for foreign products. 
The war tax is imposed on crucibles, though these are 'otherwise on the free 
list. 

The United States tariff on graphite and graphite products is as under : — 

Graphite, plumbago or black lead Free 

Black lead, advanced in value 15 per cent. 

Crucibles, black lead 15 " 

Crucibles, plumbago 20 " 



164 



Exports of Graphite from Canada, 1910-1918.* 



Year. 


Crude ore and 
concentrates. 


Manu- 
factures. 


Total 
value. 


Short Tons. 


Value. 


Value. 


1910 


788 
813 
1,654 
1,642 
919 
263 
311 
112 
664 


$53,008 
43,249 
70,763 
85,368 
50,528 
12,009 
13,114 
7,455 
32,710 


, $ 66,658 

33,956 

58,920 

24,284 

72,718 

84,316 

304,919 

384,505 

205,993 


$119,666 


1911 


77,205 


1912 


129,683 

109,652 

123,246 

96,325 


1913 

1914 


1915 


1916 


318,033 


1917 


391,960 


1918 


238,703 







Reports of the Department of Customs. 

Exports of Graphite from Canada, by Countries, 1910-1918.* 





Crude ore and concentrates. 


Manufactures of plumbago. 


Calendar Year. 


Great 
Britain. 


United 

States. 


Other 
Countries. 


Great 
Britain. 


United 
States. 


Other 
Countries. 




Short 
Tons. 


Value. 


Tons. 


Value. 


Tons. 


Value. 


Value. 


Value. 


Value. 


1910 


223 
30 
59 
19 

77 


$16,453 
3,631 
4,984 
1,700 
6,730 


556 
752 
1,550 
1,618 
814 
263 
311 
112 
664 


$35,555 
36,295 
62,680 
82,758 
41,168 
12,009 
13,114 
7,455 
32,710 


9 
31 
45 

5 

28 


$1,000 

3,323 

3,099 

910 

2,630 


$ 3,051 
2,289 
3,932 
3,278 
12,051 
2,381 
5,450 
3,115 


$ 63,466 

30,062 

46,796 

20,279 

58,816 

=81,467 

299,256 

381,226 

205,761 


$ 141 


1911 


1,605 


1912 


8,192 


1913 


727 


1914 


1,851 


1915 


468 


1916 










213 


1917 










164 


1918 










232 

















* Reports of the Department of Customs. 

Imports of Graphite into Canada, 1910-1918.* 



Calendar Year. 


Plumbago, 

not 

ground. 


Ground 

and 

manufactures. 


Crucibles, 

clay or 
plumbago. 


1910 


$ 4,867 

4,940 

7,249 

9,375 

801 

3,436 

3,231 

47,218 

93,956 


$ 55,090 
51,192 
65,911 
72,887 
49,478 
41,681 
99,919 
123,991 
132,821 


$ 52,896 


1911 


56, 814 


1912 


82,324 


1913 


73,971 


1914 


49,913 


1915 


106,761 


1916 


520,341 


1917 


798,004 


1918 


113,856 







* Reports of the Department of Customs. 



165 



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Domestic Consumption of Graphite. 

From data furnished to the Mines Branch 1 in 1912-13, the total annual 
consumption of graphite by Canadian manufacturers at that time amounted 
to 950 short tons. Of this amount, 192 tons represented domestic, and 
758 tons imported graphite. 

The bulk of the graphite used went to the foundry facings, stove 
polish and paint trades. The following table shows the consumption by 
industries : — 





Number of 

firms using 

graphite. 


Domestic, 
•tons. 


Imported, 
tons. 


Total, 
tons. 






2 

267 

13 

12 

18 

1 

6 




9 
351 

17 
270 

109 


9 




78 

1 

20 

81 

7 
5 


429 




18 




290 


Paints 


190 




7 


Various 


2 


7 






Total 


319 


192 


758 


950 







The above list of industries has since been increased by at least three, 
namely, dry battery, crucible, and pencil. The first-named uses chiefly 
artificial graphite produced at Niagara Falls, Ont. In crucibles, both 
domestic and imported graphite is used, and in pencils, imported amor- 
phous graphite. 

Prior to 1915, a certain amount of Ceylon plumbago was imported 
for use in the best grades of foundry facing, but the trade at the present 
time uses chiefly Mexican, Korean, American, and domestic graphite. 

The paint trade uses both artificial and imported amorphous graphite. 

In powder and shot polishing, Mexican amorphous graphite is used. 

Both flake and amorphous graphite is employed in lubricants. In 
addition, the Acheson Oildag Company, at Sarnia, Ont., manufacture so- 
called "deflocculated graphite" — a very finely divided artificial graphite — 
for use in their lubricating compound. 

The Dominion Crucible Company, with plant at St. Johns, Que., 
commenced operations in 1916, and is the first works of the kind to be 
established in Canada. The output of this plant has been confined to 
date to special order crucibles and accessories, but it is intended to enter 
the market in competition with English and American makers. At the 
present time, the bulk of the crucibles consumed in Canada are believed 
to be of English manufacture. 

A list of names and addresses of Canadian consumers of graphite 
will be furnished on application to the Director, Mines Branch, Department 
of Mines, Ottawa. 

General Review of the Industry. 

The great increase in the price of crucible flake, due to the war, did not 
lead, in Canada, to the increased mining activity that perhaps might have 
been anticipated. No new mines or mills came into operation, and a large 

1 Frechette, H., Report on the Non-Metallic Minerals used in the Canadian Manufacturing 
Industries, Mines Branch, 1914. 
67945—12 



168 

proportion of the existent mills were idle or in only intermittent operation. 
This may be ascribed to a combination of causes, amongst which figures 
prominently the lack of success which has for years past attended 
efforts to evolve efficient mill processes for the refining of graphite in this 
country. This, coupled with the great general increase in the cost of 
labour and materials in the last few years, has effectually discouraged the 
investment of capital in an enterprise which, while offering possibilities 
during a period of excessive, war time prices, in ordinary times has yielded 
only slight returns and then only with the most capable of management 
and under exceptionally favourable conditions. In a number of instances, 
large mills, out of all proportion to the size of the ore-bodies as determined 
at the time of their construction, have been erected at great expense, and 
owing either to lack of ore, expense of running, or a combination of these 
causes, have been in only intermittent operation ever since. Most of the 
mills erected in recent years have been equipped with a dry process of 
concentration, consisting in repeated crushing by rolls of flour mill type, 
with screening between successive crushing operations, as well as treatment 
on dry tables. Such an installation required an excessive amount of floor 
space and often an elaborate system of elevators, added to which the ore 
required to be kiln-dried prior to milling. The above called for a mill 
building of large size, relatively high power consumption and a large 
expenditure for fuel for firing the boilers, heating the plant in winter, and 
drying the ore. While wood fuel can usually be obtained in the vicinity 
of the mines, coal has sometimes been used for firing the boilers; this 
involved considerable expense for haulage, since many of the mills are 
situated at a considerable distance from rail. 

Dry methods for the concentration of graphite first came into promi- 
nence in Canada about the year 1906, and between 1906 and 1912 nine mills 
were installed with dry concentrating machinery. The process was adopted 
to supersede the wet system of buddies, originally employed in the older 
mills of the Buckingham district, in Quebec. Speaking generally, while 
there may have been some exceptions, dry concentration of graphite by the 
above methods has proved a failure in all respects. The expense involved 
has been high; a high grade of product has been obtained with difficulty 
and generally at the expense of an excessive loss of graphite in the tailings 
and the destruction of an undue proportion of the larger flake in the ore. 
Recent experience in the Alabama field, where a number of dry mills using 
similar or modified styles of concentrating machines have been erected in 
the last two or three years, has been along similar lines, and in various 
instances the dry installations have been discarded in favour of some form 
of wet concentration. 

Some part of the failures that have attended efforts to develop the 
graphite industry in Canada has frequently been ascribed to the impersis- 
tence of the ore-bodies. While this is doubtless true in the case of a number 
of properties upon which mills have been erected, it is not to be inferred 
that all or even the majority of the known deposits are of such nature, and 
any such statement requires certain qualifications. For one thing, up to 
comparatively recently, few attempts to prove ore-bodies by diamond- 
drilling had been made, and opinions on the extent of deposits were based 
merely on outcrops or an insignificant amount of surface work. 

The great majority of Canadian graphite deposits are represented by 
graphitic gneisses and limestones, originally bedded sediments, which have 
been subjected to an extreme degree of dynamic and contact metamorphism 



169 

accompanied by intense squeezing, folding, fracturing, and intrusion, so 
that they, together with the rocks intrusive into them, now form an 
exceedingly complex series with most involved structural relations. It is 
evident that little that is definite can be learned about the size and form of 
ore-bodies forming an integral part of such a complex from mere surface 
indications, and even underground work will often fail to reveal anything 
of a really definite nature. Little underground mining has been carried 
out, however, the majority of workings being shallow and open-cast, so 
that our knowledge of the deposits is necessarily scanty. What holds good 
in the case of any one particular deposit, also, could probably not be taken 
as a criterion in the case of another, owing to local variations in the struc- 
tural relations of the rocks. Hence, apart from actual mining operations, 
diamond-drilling is the only reliable method of ascertaining the extent of 
graphite ore-bodies, and it is apparent that this fact is becoming recognized, 
five properties having been drilled during the past few years — three of 
them in the last half of 1918. 

An additional feature that has some bearing on the question of the 
impersistence of ore-bodies is that Canadian graphite deposits, as a general 
thing, are apt to vary considerably in richness, and that operators usually 
confine their attention to the better class of ore (10-20 per cent grade) and ! 
regard the leaner portions of an ore-body as not worth taking out. This 
practice has arisen through the difficulties and expense attending the con- 
centration and refining of graphite, it being found that ore running over 
10 per cent of graphite might be considered of commercial grade, while 
anything much under this percentage was too expensive to treat. Fre- 
quently, in the case of the graphitic gneiss ore-bodies, the rich ore occurs 
as a succession of streaks or lense-shaped bodies, that gradually merge 
into the adjacent non-graphitic country rock, and are separated along their 
strike by patches of lower grade ore or barren rock. With cheaper methods 
of concentration, much of this lower grade ore (5-10 per cent graphite) 
might very well be utilized; in this connexion, it may be noted that the 
milling ore in Alabama does not average over 3 per cent of graphite, the 
Pennsylvania ore from 3 to 5 per cent and the New York ore 5 to 6 per 
cent. The two former are, however, soft and extremely easy to crush , 
whereas the Canadian gneiss ores are un weathered and hard. 

While, therefore, the statement that Canadian graphite ore-bodies are 
generally small and impersistent is correct in the sense that what has here- 
tofore been considered milling ore is apt to occur in rather small and 
irregular bodies, such bodies are often bordered or connected by masses 
of ore of lower grade, representing material whose graphite content may 
possibly be capable of profitable recovery by improved methods of con- 
centration. 

Much interest has been shown in the last year or two in the possibilities 
of oil flotation for the concentration of graphite ores, and it has been 
demonstrated that by this system flake graphites can be treated both 
cheaply and efficiently. The elimination of the preliminary drying of the 
ore, necessary in all methods of dry concentration and in surface tension 
or film flotation, is an important consideration from the standpoints of 
expense and mill capacity. Additional features are, that a much smaller 
mill building, involving less initial expenditure, is required to treat an 
equal tonnage of ore as compared with dry concentration; that there are 
fewer machines and appliances requiring constant attention and repairs, 

67945-1 2* 



170 

and that a smaller force of men is required for operation of the plant. A 
number of the graphite mills in Alabama are employing oil flotation 
machines of one type or another at the present time, and the system has 
also been applied successfully to Pennsylvania ore. In both cases, the 
ore treated is of relatively low grade, carrying only 3 to 5 per cent of graphite. 
Oil flotation has also been installed recently (September, 1918) at the mill 
of the American Graphite Company, in New York state, and is reported 
to be giving every satisfaction. The New York ore is similar in its general 
characteristics-^nardness, texture and associated minerals — to the 
Canadian graphitic gneiss ores. A number of tests with oil flotation have 
lately been made on Canadian ores, and a Callow plant was installed in 
August, 1914, at one of the mines in the Buckingham district. Unfortu- 
nately, however, the mill was destroyed by fire before the system had had an 
opportunhr^ of being properly tried out. 1 

Thus, while it must be admitted that graphite enterprises in Canada 
in the past have been attended by numerous failures, this result has, in 
many cases, been due largely to inefficient and expensive methods of 
concentration that rendered profitable the treatment of only the richer 
portions of ore-bodies; could not be depended upon to produce either a 
clean or a standard grade of product; made poor recovery of the graphite 
in the ore; and necessitated frequent shut downs of the mills to effect 
repairs. In not a few cases, also, capital was expended on the erection of 
mills without proper investigation of the amount of ore available. 

A pronounced recrudescence of interest in the possibilities of Canadian 
graphite has lately been evidenced, and it is to be hoped that, with efficient 
management and a proper appreciation of the difficulties attending the 
development of deposits and the treatment of graphite ores, the industry 
may recover from its depression, and the production of flake graphite 
proceed on more profitable lines than heretofore. The fact, however, 
must not be ignored that the prices that have obtained for crucible flake 
graphite during the war period have been abnormal, and that with reduced 
ocean freight and insurance rates, Canadian and American graphite generally 
may expect to find a serious competitor in Madagascar flake. The pro- 
duction of this material has risen rapidly during the last four years, despite 
embargoes and transportation difficulties, and the resources of graphite 
appear to be very large. Cheap native labour, also, even with the some- 
what crude concentrating and refining methods that are largely employed, 
enable the Madagascar product to be placed on vessels at a very low cost. 

The fact too, that in steel melting, electric furnaces have in recent 
years come into decided prominence in the United States, (hitherto, the 
principal market for Canadian graphite) and that there are indications 
that in the brass industry, also, electric melting may ultimately largely 
supersede crucible melting, must not be lost sight of when the development 
of the Canadian graphite industry is considered. 

It is perhaps, pertinent to state here that in the opinion of prominent 
New York graphite importers, in order to compete in the American graphite 
market when normal conditions are re-established, Canadian crucible flake 
graphite will have to be produced at a price of about 5 cents per pound. 

Review of Market Conditions, 1914-1918. 

Graphite, at the present day, is employed in so many branches of 
industry that the supply can hardly meet the demand. At the same time, 

1 Three Canadian mills have since been equipped with this system of oil flotation. 



171 

any one particular type of graphite (crystalline, flake, amorphous, or 
artificial) is particularly adapted to certain lines of work, and thus the 
various industries have come to utilize only that kind which best suits 
their needs. A case in point is the crucible industry. In the first crucibles 
made, Bavarian flake graphite was used, but, with the discovery of the 
Ceylon plumbago deposits, flake graphite was largely discarded in favour 
of the crystalline form. In the same way, pencils were formerly made from 
either crystalline or flake graphite, but are now manufactured almost solely 
from amorphous graphite. During 1918, in the United States, curtailment 
of imports of Ceylon plumbago led to the use of an increased proportion of 
flake graphite in crucibles, and experiments have been undertaken by the 
Bureau of Standards with a view to determining whether plumbago cannot 
be replaced to a still larger extent by flake without any serious detriment 
to the quality of the crucibles so made. 

Thus, while in many of the industrial uses of graphite, a certain type 
of graphite is considered essential for best results, in those industries which 
consume the bulk of the graphite used, some one of the other forms of 
graphite than that at present employed could probably be substituted, 
either wholly or in part, without serious detriment 1 . 

In view of the dependence of Canadian producers on the American 
market, and the fact that the great bulk of Canadian graphite is exported 
to American consumers, the following notes on the graphite situation in the 
United States are given below. 

Several factors have had an important bearing on the graphite 
situation in the United States during the war period. At the outset, it 
should be noted that the graphite market is very largely regulated by the 
Ceylon supply, and that a shortage of Ceylon plumbago, with a corres- 
ponding rise in its price, stimulates the flake graphite industry. The year 
1913 saw a decrease in production and a material increase in price of Ceylon 
graphite, while in the same year Madagascar came prominently to the 
fore as a producer of flake. High prices prevailed generally during the 
year and resulted in relatively small sales. In 1914 the market declined 
considerably, and during the latter months, owing to the embargoes 
imposed by the British and French Governments on Ceylon and Madagascar 
shipments respectively, production in these countries virtually ceased. 
The embargoes were first of all imposed only against Germany and Austria, 
but were later extended to all neutral countries, the purpose being to prevent 
shipments finding their way to enemy countries and to ensure sufficient 
supplies for British and French crucible firms. The low stocks of Ceylon 
graphite laid in, in 1913, followed by the total cessation of shipments in 
1914, caused a serious shortage of crucible graphite in the following year, 
and all grades of flake were eagerly sought and fetched high prices. Owing 
to the large munitions contracts placed in the United States, represent- 
ations were made to the British Government early in 1915 by American 
crucible makers and resulted in the embargo on Ceylon graphite being 
partially lifted in May of that year and totally in September. In the 
course of a few months the situation was relieved to a large extent, owing 
to the special efforts made by the British Government to facilitate ship- 
ments. During 1915-16, the price of crucible graphite rose to an unprece- 
dented figure. Whereas, in January, 1915, the best Ceylon lump sold ex 
dock New York for 9 cents per pound, in January, 1916, it was bringing 20 

1 See A. V. Bleininger, Chemical and Metallurgical Engineering, Sept. 27, 1918, p. 467. 



172 

cents, and in the following April had still further advanced to 27 cents. 
The great increase was partly due to increased mining costs, but chiefly to 
high freight and insurance rates. In some cases, the latter amounted to 
over 8 cents per pound. Shortage of bottoms and high freight charges 
resulted in very little of the lower grades of Ceylon graphite being imported, 
the great bulk of the imports consisting of best lump. 

While the embargo by the French Government on Madagascar ship- 
ments had been modified early in 1915, practically the whole of the island's 
production for that year went to France. Owing to difficulties of trans- 
shipment at Marseilles and the prohibitive cost of direct shipments to the 
United States, the price of Madagascar flake rose to 12 cents per pound 
ex dock New York during the latter part of 1915, as compared with 4-5 
cents before the war. 

In 1916, lack of bottoms and the insistent demand for crucibles rendered 
it increasingly difficult for manufacturers to obtain sufficient supplies of 
Ceylon graphite, and other kinds of graphite entered into crucible manu- 
facture to a larger degree than in any previous year. As a result, the price 
of American flake rose to 13-16 cents per pound, according to quality, as 
compared with 6-8 cents in 1913, and the production was more than double 
that of the latter year. 

Similar conditions persisted on into 1917, but in the latter part of the 
year, shipments more than met the demand, owing to the falling off of 
munitions orders, and the consequent decreasing demand for crucibles. 
Best Ceylon lump brought the maximum price of the war period, 29-32 
cents per pound, ex dock New York, in 1917, and Madagascar No. 1 flake 
brought 14-16 cents. During the early part of 1918, crucible makers and 
foundries had large stocks of pots on hand, and many crucible factories 
were working at only half their capacity. At the same time, graphite 
shipments ordered for future delivery were accumulating, so that supplies 
of both Ceylon and flake graphite soon became considerably in excess of 
requirements. Reduction in marine freight and war insurance towards 
the end of the year brought the price of Ceylon plumbago down to about 
30 per cent below the figures prevailing in the early part of the year. To 
illustrate the downward trend in prices, the figures for the different grades 
in 1917 and 1918 are shown below: — 

Average prices of Ceylon plumbago, ex dock New York, during 1917 and 1918. 



Grade. 


1917. 


Feb., 1918. 


Dec, 1918. 


No. 1 lump 


30 cents per pound 
20 " 
12 " 


25 cents per pound 
18 " 
11 " 


18 cents per pound 


No. 1 chip 


14 " 


No. 1 dust 


10* " 







The total imports of Ceylon graphite into the United States in 1917 
are estimated at about 80,000 barrels, or 26,666 tons. The spot price of 
the mineral in this year suffered some decline, and the c.i.f. New York 
price was caused largely by the excessive ocean freight charges — 536 
shillings per ton. 

As stated above, the rise in price of crucible grades of graphite has 
given a very considerable impetus to the flake graphite industry of the 
United States, the most marked effect being seen in the Alabama field, 
where over forty mills were in operation and under construction by 1917. 



The increase in production of refined crystalline graphite of all grades 
between 1913 and 1917 amounted to nearly nine million pounds. 

The graphite industry, in common with many others, has been sub- 
jected to a variety of war time restrictions. In order to control the impor- 
tations of graphite into the United States, a body called the Plumbago- 
Graphite Association, Inc., was formed in 1917, under the direction of the 
War Trade Board. This body was composed of prominent graphite 
importers and brokers, and all foreign shipments of graphite had to be 
consigned in care of the Association. The Association was also empowered 
to collect from manufacturers and importers periodical statements of 
stocks on hand, consumption, etc., for the information of the Government, 
with a view to providing for such allotment and distribution of graphite 
and plumbago supplies as would ensure the best interests of manufacturers, 
importers, and the country in general. By a War Trade Board ruling of 
March 23, 1918, restriction of graphite and plumbago imports was ordered, 
to the extent of limiting the total quantity of such imports during the last 
six months of 1918 to 5,000 tons. This ruling, however, only applied to 
ocean borne shipments and did not affect rail or lake borne Mexican and 
Canadian supplies. By a subsequent ruling, 1,000 tons of the 5,000 tons 
allowed was permitted entry previous to July 1. On July 3, however, a 
further ruling was made prohibiting all further overseas imports for the 
remainder of the year. 

In common with other articles, all graphite importations into the 
United States have been made subject to license, and on October 2, 1918, 
the July 3 ruling was modified to grant such license, in the case of crucible 
grades of graphite, when satisfactory guarantees were given that the 
ultimate consumers of such graphite were using at least 20 per cent of 
domestic or Canadian flake in the manufacture of their products. By 
the same amendment, all importation of amorphous graphite, other than 
Mexican or Canadian shipments, was prohibited. Plumbago for any 
purpose other than crucible manufacture was to remain fully restricted, 
and the importation of foreign made crucibles was likewise prohibited. 

On January 16, 1919, all restrictions governing the importation of 
foreign graphite or plumbago and the required use of 20 per cent or more 
of domestic or Canadian flake in crucible mixtures were removed. 
Restrictions against the importation of foreign crucibles were also removed. 



174 



CHAPTER IX. 

SOURCES OF THE WORLD'S GRAPHITE SUPPLY. 

Graphite is a most widely distributed mineral, and is found in prac- 
tically all parts of the world. The bulk of the world's production is at 
the present time derived from some ten countries, but deposits are known, 
and have in many cases been worked in a small way, in a number of others. 
Many of the occurrences, however, consist of material that it has not 
proved practicable to utilize, whether through lack of adequate refining 
processes to treat the ore or by reason of the graphite being of unsuitable 
character. 

The crucible trade, consuming 75 per cent of the world's total pro- 
duction of graphite, has for many years been supplied mainly from Ceylon, 
the natural purity of the Ceylon product and its superiority for this class 
of work, combined with cheap labour and low freight rates, enabling it to 
compete with flake graphite in practically all markets. In the last few 
years, however, increasingly large amounts of flake have been derived from 
Madagascar, and this material has successfully demonstrated its suitability 
for certain kinds of crucible work. The fact that Madagascar graphite 
can be mined cheaply, due to native labour and its mode of occurrence, 
and that expensive refining processes are not required to fit it for the 
market, will probably lead to its more extensive use, and graphite from 
this source of supply seems likely, when normal export and freight conditions 
are established, to exert considerable influence over the flake graphite 
industry in other countries. 

Brief notes on the graphite industry in the world's chief producing 
countries are given below. 1 

Austria. 

Austria, in 1913, the last year for which statistics are available, was 
the largest producer of graphite in the world, the output for the year being 
54,500 short tons. The greater part of the Austrian graphite is amorphous 
in character, or is so finely crystalline that it cannot properly be termed 
flake, and it is, therefore, not of crucible grade 2 . 

The Austrian production is derived from deposits in four distinct 
fields. In Bohemia, graphitic slates or schists were worked as far back 
as 1767 in the Krumau and Schwarzbach districts. The ore undergoes a 
wet process of concentration, and the production in 1908 is given as 22,160 
metric tons. Most of the graphite is consumed in foundry work. The 
Bohemian deposits are regarded as an easterly extension of the Bavarian 

1 For fuller details see the following: — 

de Launay, L., La Geologie du Graphite, Annales des Mines, X Series, Vol. 3, 1903, pp. 49-86. 
(Descriptions of graphite deposits in various countries.) 

Dammer, B. und Tietze, O., Die Nutzbaren Mineralien, Stuttgart, 1913, Vol. I, pp. 57-85. 
(Describes the world's graphite deposits and gives notes on uses, etc., of graphite.) 

Stutzer, O., Die Nicht-Erze, Berlin, 1911, pp. 1-88. (Discusses the occurrence and geology of 
the more important graphite deposits in various parts of the world.) 

2 Breitschoff, J., Das Graphitvorkommen in Sudlichen Bohmen, Zeitschr. f. Berg. u. Htitten- 
wesen, Vol. 58, 1910, pp. 131, 153, 167. (Describes the southern Bohemian graphite deposits and the 
methods of mining and refining.) 



175 

(Passau) ore-bodies; the latter having suffered a greater degree of meta- 
morphism, with consequent conversion of the graphite to the flake form. 
In the adjoining province of Moravia, graphite is mined at a number of 
localities. Eight mines were in operation in 1908, and the production 
totalled 10,285 metric tons. A small amount of graphite is obtained also 
in the vicinity of Spitz, Lower Austria. In Styria, a number of deposits 
have been worked; all of the graphite is amorphous in character and the 
carbon content varies widely, from 42 to 87 per cent. Some of the mines 
yield a soft, earthy graphite and others a hard material, resembling 
anthracite. Four mines in 1908 produced 10,000 metric tons. 

Ceylon. 

The Ceylon 1 graphite deposits came into prominence as far back as 
1834, and have grown steadily in importance. The island owns a practical 
monopoly of the world's supply of crystalline graphite, or plumbago, and 
since this form of graphite, owing to its greater refractoriness over flake 
and other kinds, is in great demand for crucibles, the deposits are of par- 
amount importance for the metallurgical industries. While Ceylon 
graphite was formerly used to some extent in pencils, practically the whole 
of the present output finds its way into crucibles. 

In 1913, the United States took one half of the island's total production 
of 32,000 tons, the remainder being divided between Germany, 7,000 tons, 
the United Kingdom, 6,000 tons, Belgium, 2,000 tons, and all other countries 
600 tons. 

The mineral occurs in veins and also, to a small extent, in the form of 
flake disseminated in gneiss and crystalline limestones. The veins alone, 
however, are the source of the entire output, and they range from mere 
seams to bodies several feet in width. Under favourable conditions, small 
stringers two or three inches in width are worked. The walls are usually 
well defined, and the adjacent country rock is not impregnated with 
graphite to a distance of more than half an inch from the veins. 

In the smaller veins, the graphite usually occurs in the form of a mass 
of parallel fibres or needles set at right angles to the vein walls. In the 
larger veins, most of the graphite exhibits a coarse, platy or foliated struc- 
ture, though fibrous graphite often occurs in a narrow zone between the 
main portion of the vein and the walls, or surrounding included masses of 
the country rock. This fibrous graphite, known as needle lump, finds 
high favour commercially. 

While usually consisting entirely of graphite, the veins sometimes 
carry other minerals in appreciable amount. Pyrites is common in dissem- 
inated form between the plates and fibres, and sometimes forms more or 
less definite bands in the central portion of the veins, and quartz occurs 
in a similar manner. Other accessory minerals are biotite mica, ortho- 
clase feldspar, pyroxene, apatite, allanite, and rutile. In some cases the 
vein material has been crushed to an earthy consistency by later tectonic 
disturbances. 



1 Abstract of an article by E. S. Bastin, in Mineral Resources of the United States, 1911, Part 
II, pp. 1094-1102. The article contains an extensive bibliography on Ceylon graphite. 

See also: Weinschenk, E., Die Graphitlagerstatten der Insel Ceylon, Abh., d.k. Bayr. Akad. 
d. Wissensch., Vol. 21, 1901, pp. 233-334. 

Weinschenk, E., Zeitschrift f. p. Geol., 1900, p. 179. 

Pettinos, C, Mining and Sorting Graphite in Far-off India, Foundry, Vol. 40, 1912, pp. 315-9. 



176 

The veins are worked either by open cast methods or by vertical 
shafts from which drifts are run. The average depth of the workings does 
not exceed 100 feet, though in a few cases 400-500 feet has been reached. 
Flooding of the workings, due to the heavy rainfall, is a great obstacle 
to deep mining. Mining appliances are, generally, extremely crude, and 
only a few of the mines are equipped with steam pumps and hoists. 

According to the "Mineral Industry", the production of graphite 
in Ceylon in 1916 was 33,411 long tons. New York prices for the various 
grades in 1917-8 were: — 



1917 



February, 1918. 



December, 1918. 



No. 1 lump. 
No. 1 chip.. 
No. 1 dust. . 



29-32 cts. per lb, 
19-22 " " 
11-13 " " 



24-25 cts. per lb. 
17-19 " " 
10-12 " " 



15 cts. per lb. 
12 " " 
9-10 " " 



The carbon content of the above grades averages 88-90 per cent for 
the lump, 70-85 per cent for the chip, and 70-75 per cent for the dust. 

In 1917, the United States took over 81 per cent (by quantity) of the 
island's output. Owing to the numerous restrictions placed on the expor- 
tation of graphite during the last few years, there has been an appreciable 
curtailment of mining, and in the last half of 1918, due to the embargo 
placed on graphite imports into the United States, the industry experienced 
stagnation. 

The mines are largely in the hands of natives, who employ only a few 
hands, and any marked falling off in the market causes many of the mines 
to shut down. 

The following table 1 shows the prices of Ceylon plumbago, ex dock 
London, that obtained from 1914 to 1918: — 



Best Lump, 


Best Chip, 


cents per pound. 


cents per pound 


7 


6* 


7 


5* 


15* 


10* 


17 


14 


23 


211 


21 


17* 


21 


17* 


16 


15 


15 


12* 


12 


7* 


12 


7* 



1914, pre-war 

1915, opening 

1915, ending. 

1916, opening 
1916, middle. 

1916, ending. 

1917, opening 
1917, middle. 

1917, ending., 

1918, opening. 
1918, ending., 



The following extracts from British technical journals, quoted in 
U.S. Geological Survey Press Bulletin, No. 399, February, 1919, give the 
latest information available regarding the graphite situation in Ceylon: — 

"The Ceylon export last year (1917) approximated to 26,000 tons. The demand 
suffered considerably by the control, especially in the matter of freights, so that a large 
number of small mines ceased to work. At the beginning of the year the number of 
properties in operation was 1,288 and at the end of the year 764, with a corresponding 
decline in the labour force of about 4,500. Naturally the boom which the industry 
experienced led to a large number of new properties being opened, but nothing fresh of any 



Courtesy of the Morgan Crucible Company, Ltd., London. 



177 

importance has been revealed. Generally speaking, the industry is said to be in an 
unsatisfactory condition, but with the restoration of free markets it is thought that the 
output can be improved up to a production of perhaps 30,000 tons a year for some years 
to come." — London Mining Journal, August 31, 1918. 

"Ceylon Graphite industry in 1917. — After about a year of stagnation the industry 
became active toward the end of 1915. This activity continued throughout 1916, which 
was a record year, the output being 33,400 tons, valued at £1,500,000. The year 1917 
commenced with every prospect of similar prosperity, the demand was brisk, high prices 
were ruling, and the Government was asking for an increased output. During the first 
6 months 13,000 tons were exported, realizing £800,000, but during the latter half of the 
year prices dropped, and by the end the demand had practically ceased. The smaller 
mines have in consequence been shut down, although the larger ones are continuing work 
and accumulating stocks. There were 1,288 mines working during the first 6 months, but 
only 764 during the second. 

"Over 3,000 new enterprises have been registered during the year, but no new valuable 
deposits have been discovered. Several abandoned workings have been restarted with 
good results. 

"The output of plumbago depends entirely on the demand and ruling prices; while 
these are favourable there is every possibility of a yearly production of 30,000 tons for 
several years. 

"The present state of the industry is decidedly bad, and very little can be done to 
mend matters until markets improve. When this occurs, the exploitation of new lands 
should be taken in hand, with a view to finding new deposits to take the place of the present 
mines as they become exhausted." — Board of Trade Journal, August 29, 1918. 

The following quotation from Commerce Reports No. 51b, December 17, 1918, gives 
a summary of the Ceylon industry for 1917: — 

"Plumbago, Ceylon's most speculative industry, again had a phenomenal year, 
owing to the demand created by the war. Toward the end of the year, however, exports 
fell off, and prospects for 1918 are not good. The total quantity shipped in 1917 was 
523,940 hundredweight, valued at $7,071,803, as compared with 668,216 hundredweight, 
valued at $7,298,128, in 1916. In 1915 the exports were valued at only $2,569,434, which 
was the record up to that time. According to the Ceylon customs returns, the United 
States took 84 per cent of the value of Ceylon's plumbago in 1917, and practically all of 
the remainder went to the United Kingdom. France is said to get her supplies from 
Madagascar. 

"During 1917 the average f.o.b. price of Ceylon plumbago was $270 per long ton, 
a slight increase over 1916. Medium to fine grades of ordinary lump ranged during the 
year from $210 to $446 per long ton, while medium to fine cjiips varied in price from 
$130 to $290 per ton." 

"Prices of Ceylon graphite at New York in the beginning of 1918 were 22£ cents 
a pound for best lump, 21 ^ for best chip and 10 to 12 for dust. At the end of the year 
prices had fallen to 15^ for best lump, 12^ for best chip and 9 to 10^ for dust. 

"Imports of Ceylon graphite during 1918 amounted to about 9,100 short tons, com- 
pared with 24,575 short tons in 1917." 

Chosen (Korea). 

Shipments of graphite from Korea commenced in 1903, and in 1913 
there were six producing mines. Most of the Korean graphite is amor- 
phous, and the carbon content of the material shipped ranges from 60 to 85 
per cent. The exports for 1916 totalled 18,704 short tons, valued at 
$243,000. Mining operations are controlled chiefly by Japanese firms, 
and most of the foreign shipments come by way of Japanese ports. 

Considerable quantities of Chosen graphite have been consumed in 
the United States, the material competing with the Mexican amorphous 
graphite for certain purposes, such as stove polish, paints, etc. The 
imports of Chosen graphite into the United States in 1917 totalled 2,500 
tons. 

Germany. 

The Passau district, in Bavaria, is well known for its deposits of flake 
graphite. Passau graphite found employment as far back as the Middle 



178 

Ages for alchemists' crucibles, and much of the production at the present 
day enters into crucible manufacture. 

The graphite is found 1 in lenses and pockets in gneiss and schists, and 
is of disseminated flake type. The graphite-gneiss is often weathered to 
considerable depths, and the ore consists largely of soft, sandy material 
that is both easy and cheap to mine. The average graphite content ranges 
from 20-30 per cent. In 1913, the last year for which figures are avail- 
able, Bavaria produced 13,263 short tons of graphite. In the same year 
Germany imported over 7,000 tons of Ceylon graphite, being the next 
largest consumer of this material after the United States. The cutting 
off of the Ceylon supply is reported to have resulted in a greatly increased 
output from the Bavarian mines. A process, was evolved nearly twenty 
3^ears ago for pressing or briquetting the smaller Passau flake into aggre- 
gates which would be more refractory, and thus better suited to crucible 
manufacture (see page 109). It is reported that this method has been 
practised extensively during the war. 

Italy . 

Graphite is found in disseminated form in the gneissic rocks of the 
Pinerolo district, in Piedmont. Most of the graphite found in these rocks 
is amorphous in character, and is regarded as metamorphosed coal or similar 
carbonaceous matter. 

While the graphite bearing zone has a considerable width, only specially 
rich ore is worked, this being found in the form of beds or lenses in the 
schists. The carbon content of the best graphite averages 70 per cent. 
No system of refining appears to have been practised, the material under- 
going only a grinding process at the mines. Similar graphite is found near 
Bagnasco, in Liguria. 

The Italian graphite production in 1916 was 9,000 short tons. The 
bulk of the output appears to find use in foundry facings. 

Madagascar . 

Madagascar has come rapidly to the front in the last few years as an 
important graphite producer. From 7,000 tons in 1913, the production 
has risen to 35,000 tons (estimated) in 1917 2 . The country is now one 
of the world's largest producers of flake graphite, and reports on the extent 
of the deposits indicate that the output may be expected to be materially 
increased 3 . The graphite is of excellent quality and is used extensively 
in crucible manufacture. Shipping restrictions and embargoes during 
1917 and 1918 materially affected the industry. Most of the output goes to 
England and France, exports to the United States in 1917 totalling 3,000 
long tons. 

The graphite occurs disseminated in schists, which carry up to 60 
per cent of graphite. These schists are found over a very large area, and 
the quantity of graphite that will be available appears to be enormous. 
At present, development of the deposits has taken place mainly in terri- 



1 Weinschenk, E., Die Graphitlagerstatten des bayrisch-bohmischen Grenzgebirges, Abh. 
d.k. Bayr. Akad. d. Wissensch., Vol. 19, 1898, pp. 509-64; Zeitschrift f. p. GeoL, 1897, p. 287. 

2 Mineral Industry, 1917, p. 310. 

3 Mining Magazine, Vol. XIV, 1916, pp. 324-330. See also Levat, M. D., Richesses Minerales 
de Madagascar, Paris, 1912, pp. 192-203. 



179 

tory adjacent to the principal transportation routes, and the graphite so 
far obtained appears to have been secured chiefly from surface deposits 
derived from the weathering down of the schists. This surface material is 
more or less clayey in character, and the graphite is extracted by either 
simply washing out the clay and sand in sluices or by passing the material 
through a rice mill (chaser or muller pan type) to break down any grit or 
lumps that may be in it, and then washing. These methods, however, 
as might be expected, recover only about 30 per cent of the graphite in the 
ore. About 60 per cent of the graphite recovered is of crucible grade. 

The ore appears to vary rather widely in character, due to the presence 
locally of varying amounts of mica and other minerals, and modified 
systems of concentrating and refining doubtless will have to be devised 
to meet local conditions once the industry becomes established along 
modern lines. 

Vein graphite resembling that from Ceylon is said to occur in certain 
localities, but such material has not figured so far to any extent in the 
exports. 

Much information on the Madagascar graphite industry up to 1914 
is contained in reports by J. G. Carter, in Daily Consular and Trade 
Reports of .the United States, January 29, 1913, and December 24, 1913. 
Abstracts from these reports are contained in Mineral Resources of the 
United States, 1913, Part II, pp. 239-244. 

Below are shown 1 the prices that obtained for Madagascar No. 1 
flake on the London market from 1914 to 1918: — 



Cents per pound . 



June 1914.. 
April 1915. 
April 1916. 
April 1917. 
Early 1918. 



7 1 

8 } War risk and rise in freight to buyer' 
10£ account. 

9 



The following data regarding the graphite situation in Madagascar 
is extracted from U.S. Geological Survey Press Bulletin, No. 399, February, 
1919: — 

Information has been received from the War Trade Board to the effect that on 
October 11, 1918, the stocks of graphite in Marseille amounted to 12,000 metric tons. 
The price asked at that time was 1,200 francs a ton at Marseille, equivalent to 10 cents 
a pound. In addition, stocks on the island of Madagascar are available at 600 francs 
a ton (5 cents a pound). The present productive capacity of the Madagascar deposits is 
estimated at 40,000 metric tons a year. Of the production in 1917, amounting to 35,000 
tons, from 10,000 to 15,000 tons were available for export in July, 1918 (Commerce Report, 
August 16, 1918, p. 630). The "Union des Producteurs de Graphite de Madagascar," 
recently offered to furnish this country annually 15,000 to 20,000 tons of flake graphite, 
minimum 85 per cent carbon, at 600 francs a ton (5 cents a pound) f.o.b. Tamatave, 
with 15 francs difference for each 1 per cent over or below 85 per cent. (Information 
from Bureau of Foreign and Domestic Commerce). During October and November the 
London price for Madagascar graphite c.i.f. British ports, as quoted by the London 
Mining Journal, was £50 a long ton (10 cents a pound). Since December 1 there has been 
practically no market and quotations have been only nominal. The issue of December 28 
stated that a single transaction in Madagascar graphite had been made at £46, ex ship 
London. 

In a recent article (Jour. Chem. Met. & Min. Soc. of South Africa, vol. 19, p. 32, 
1918) it is stated that the exports from Madagascar in 1917 amounted to 27,000 metric 



Courtesy of the Morgan Crucible Company, Ltd. 



180 

tons, but that by the middle of 1918 mining had practically stopped on account of lack 
of snipping, the principal buyer (Morgan Crucible Co.) having reduced its purchases 
to one-sixth of the former amount. 

L. de Pritzbauer, in a recent article (L'Avenir de Madagascar, Chimie et Industrie, 
vol. 1, p. 679, 1918) states that it is feared that there will be great overproduction after 
the war and that it will be necessary for the colony to take measures to maintain the 
production within reasonable limits. The costs of mining and transportation to a seaport 
are estimated at 450 to 500 francs per metric ton (about 4 cents a pound). The tenor 
of flake in favourable deposits is 20 to 30 per cent, but anything over 10 per cent is con- 
sidered workable. 

It has been the policy of the War Trade Board to give preference to import licenses 
for Ceylon graphite. Consequently only 970 short tons were imported from Madagascar 
during 1918 against 4,393 short tons during 1917. 

Mexico. 

Large deposits of amorphous graphite exist in the State of Sonora 1 . 
The graphite has been formed by the metamorphism of coal seams, and the 
beds are enclosed in altered sandstone. The whole series is extensively 
intruded by granite, which has effected the metamorphism. The average 
graphitic carbon content of the main bed worked is 86 per cent, but picked 
samples are said to run as high as 95 per cent. 

The deposits are owned and worked by the United States Graphite 
Company, of Saginaw, Michigan, to which point the crude graphite is 
shipped for refining. The refining process consists of grinding and air- 
floating. (See p. 64). 

Sonora graphite is much in demand for pencil manufacture, and it is 
also used in lubricants, graphite brushes, paints, electrotyping, powder 
glazing and various other branches of industry. 

South Africa. 

According to P. Wagner 2 , a considerable part of the domestic demand 
for graphite and graphite products in South Africa is supplied from a 
deposit now being worked in the Transvaal. The occurrence is said to be 
a narrow lense of very fine flake graphite lying between pyroxenite and 
quartzite. The crude ore is shipped to Johannesburg, where it is milled 
and worked up into various graphite products, including paints, lubricants, 
foundry facings, boiler graphite, etc. 

Spain. 

A small production of graphite of crucible grade has been secured 
intermittently from deposits in the province of Malaga. Attention is now 
being directed to flake graphite occurrences in the province of Huelva 3 , 
and there appears to be some prospect of refining plants being erected to 
treat the ore, which carries up to 10 per cent of graphite. 

In 1916, Spain produced 1,364 short tons. 

1 Hess, F. L., Graphite Mining near La Colorado, Sonora, Mexico, Eng. Mag., Vol. 38, 1909, 
pp. 36-48. Hornaday, W. D. f The Santa Maria Graphite Mines, Mexico, Min. and Eng. World, 
December 7, 1912. 

2 South African Journal of Industries, Vol. I, No. 6, 1918, p. 497. 

3 Mining Magazine, September, 1918, p. 133. 



181 

United States. 

Graphite is found in many localities, and deposits have been worked 
in seventeen states, but the greater part of the production of flake 
graphite has so far been derived from New York, Pennsylvania, and 
Alabama. The occurrences include all three varieties of graphite, flake, 
amorphous and crystalline or vein graphite. The production of flake 
graphite in 1917 totalled 5,292 short tons, and of amorphous, 8,301 tons. 
Details of marketed production and value are given below : — 

Domestic Graphite Sold in the United States in 1917. x 





No. 1 and 

No. 2 Flake. 

Pounds. 


Other 
Grades. 
Pounds. 


Total. 


Amorphous. 




Pounds. 


% 


Tons. 


$ 


Alabama 


4,295,233 

1,656,897 

549,783 

315,000 


1,927,862 

1,284,143 

255,162 

300,000 


6,223,095 

2,941,040 

804,945 

615,000 


719,575 
261,548 

77,475 
35,800 






New York 






Pennsylvania. 






Other States* 


8,301 


73,481 






Total 


6,816,913 


3,767,167 


10,584,080 


1,094,398 


8,301 


73,481 







*Crystalline: Alaska, California, Montana, and Texas. 
Amorphous: Colorado, Michigan, Nevada, and Rhode Island. 

The actual production for the year totalled 14,000,000 pounds, but 
owing to various causes (embargoes and freight congestion) a considerable 
amount remained over as stocks on hand at the mills. 

With the exception of a small quantity produced in California and 
Texas, all of the flake graphite produced during the year was derived from 
Alabama, New York, and Pennsylvania. The production from Alaska 
and Montana consisted of crystalline or vein graphite, resembling that 
from Ceylon. 

According to a preliminary estimate by H. G. Ferguson, of the Geolo- 
gical Survey, the amount of flake graphite produced in the United States 
in 1918 was nearly 6,500 short tons, valued at about $1,500,000. This 
is the largest output so far recorded. Approximately 4,400 tons of the 
above amount represented No. 1 and No. 2 flake, the remainder being 
dust and low grade flake. Alabama produced over one-half, and New 
York about one-fourth of the total output. The production of amor- 
phous graphite is estimated at 7,000 tons. 

Below are given brief notes on the more important of the American 
graphite occurrences. 

Alabama. 

The Alabama graphite deposits lie in Clay, Chilton, and Coosa counties, 
in the vicinity of Ashland, Mountain Creek, and Goodwater, respectively. 
All of the occurrences are similar, and consist of rather low grade graphitic 
schists carrying from 3 to 5 per cent of graphite. In the majority of cases, 
the ore worked consists of the rather soft, weathered material that is found 
above ground-water level, or to a depth of some 50-75 feet below the 
surface. The large quantity of such ore available makes it unnecessary 
to mine the underlying, harder rock, which is more difficult to mill. The 
ore consists for the most part of quartz, with subsidiary sillimanite, mica, 
graphite and clayey material containing iron oxide. Pyrites and feldspar 

1 Mineral Resources of United States, Part II, 1917, p. 100. 



182 

are present in the fresh, unweathered rock. Much of the ore is taken out 
with the pick, and all the workings are open cast. 

The graphitic strata form conformable bands in a mica schist forma- 
tion, the bands ranging from 30 to over 100 feet in width and extending 
for many hundreds of feet along the strike. The graphitic bands carry 
very little mica, and there is great uniformity throughout in the size and 
character of the flake. 

The size of the graphite flakes is rather on the small side, compared 
with that of the flake from the Pennsylvania, New York, and Canadian 
deposits. 

The graphite industry in Alabama underwent greater expansion in 
1917 than in any preceding year. While only three companies were active 
in 1913, the number of mills operating or under construction in 1917 was 
over forty, and more than sixty companies had been incorporated. 

A variety of concentrating and refining methods is practised, including 
film flotation by wet boxes, Callow, Minerals Separation and Simplex 
oil flotation, electrostatic separation and dry table concentration. The 
Alabama Graphite Producers' Association was formed in 1917 to secure 
mutual cooperation between the various operators, with the object of 
standardizing mill products and assisting the industry in its development. 

For descriptions of milling methods see Chapter VII. 

i 

New York. 

The Adirondack region of New York 1 has long been an important 
producer of flake graphite, the deposits being situated for the most part 
in Essex, Warren, and Saratoga counties, in the neighbourhood of 
Ticonderoga and Saratoga Springs. The largest producing mine in the 
United States — that of the American Graphite Co., a subsidiary of the 
Joseph Dixon Crucible Co., of Jersey City — is located at Graphite, near 
Lake George. 

The graphite bearing series of this State consists of metamorphosed 
Pre-Cambrian rocks, chiefly crystalline limestones, schists and gneiss, 
the whole being extensively intruded by pegmatites. In their general 
nature, the deposits are similar to those of the Quebec region, in Canada. 
In some cases, the rock worked is a crystalline limestone carrying 3-5 
per cent of graphite; in others, graphitic gneiss or schist forms the bulk 
of the ore. At some localities, somewhat pockety masses of graphite 
occur as contact deposits between limestone and pegmatitic intrusions, 
this mode of occurrence closely paralleling that at Grenville, St. Remi, 
and other localities in the Province of Quebec. Small veins of graphite 
also occur, but are considered too narrow to work. As a general thing, 
the milling ore of this region is somewhat lower in graphite than that worked 
in Canada, 5-8 per cent probably being the average of the various mines. 

The number of producing mines in the State in 1917 was three. A 
variety of concentrating methods has been employed in the different mills, 
including the dry process by means of rolls and screens, but wet concentra- 
tion by means of buddies has been the system most generally practised. 
The mill of the American Graphite Company has been recently (September, 
1918) equipped with the Callow oil flotation svstem. (See also Chapter 
VII.) 



1 Newland, D. H., The Mining and Quarry Industry of New York State, New York State 
Museum Annual Bulletins, 1904-18. Ailing, H. L., The Adirondack Graphite Deposits, New 
York State Museum Bulletin, No. 199, July 1917. 



183 

Pennsylvania. 

The graphite deposits of Pennsylvania 1 are situated in the Pickering 
valley, near Byers and Chester Springs, in Chester county. The graphite- 
bearing rock is a gneiss with local mica schist phases. Numerous accessory 
minerals occur, and the rock is extremely variable both in mineralogical 
composition and texture. Pyrites and pyrrhotite are commonly present 
in considerable amount in the graphitic bands. The rocks have suffered 
much deformation, and it has not proved possible to trace any one band 
of graphite for a very great distance. There are a number of graphitic 
bands, which as a rule merge gradually into the enclosing gneiss. The 
amount of graphite carried varies from 3 to over 10 per cent and probably 
averages about 4 to 5 per cent. The width of the bands ranges from 6 to 
over 100 feet. The gneiss is intruded extensively by pegmatite dikes, 
and these also usually contain some graphite. Small veins of graphite 
also are found, but they have in no instance proved large enough to work. 

Mining operations are in most cases confined to the decomposed surface 
rock, which extends to a depth of about 100 feet. This rock is so soft 
that it can readily be broken down with the pick, and the ore fed to 
the mill is in some cases practically a gravel. A great deal of the mining 
is by open cast methods, though in some cases drifts and shafts are employed. 

Much of the flake is rather larger than that usually found in rocks 
of the above type; and the ore being soft and requiring little crushing, 
the proportion of No. 1 flake recovered is relatively high. 

Five companies reported production in 1917. Various methods of 
concentration have been employed in the different mills, log- and rake- 
washers, buddies, oil flotation, and dry concentration by means of rolls and 
screens all having been tried. (See Chapter VII). 



CRYSTALLINE GRAPHITE OR PLUMBAGO. 

Alaska. 

Small shipments of hand picked crystalline graphite have been made 
during the last ten years from deposits in the Seward peninsula. The 
graphite occurs in the form of lenses enclosed in mica schists. The lenses 
have a width of 1 to 6 feet. 

Montana. 

Crystalline graphite occurs near Dillon, in veins ranging up to 16 
inches in width. The material of the veins consists of practically pure 
graphite in the form of aggregates of bladed or fibrous crystals. The 
deposit has been worked for several years past, the method of working 
being bj^ means of an adit, from which a shaft has been sunk on the vein. 
Two levels have been driven from the shaft at depths of 75 to 100 feet 
below the adit. The graphite occurs in irregular veins following fracture 
planes in quartz- or mica-schists and pegmatite, and the general mode 
of occurrence would seem to be similar to that of the graphite veins found 
in the Grenville series in Canada. 



1 Miller, B. L., Graphite Deposits of Pennsylvania, Pennsylvania Topographic and Geologic 
Survey Commission, 1912. 

67945^13 



184 

FLAKE GRAPHITE. 

California and Texas. 

Small amounts of flake graphite have been produced in recent years 
in California (Los Angeles and San Diego counties) and Texas (Llano and 
Burnet counties) . In both these States, the graphite occurs in the dissemin- 
ated form in schists. 

AMORPHOUS GRAPHITE. 

Colorado. 

Deposits of amorphous graphite are worked in Chaffee and Gunnison 
counties. Both occurrences are regarded as altered coal seams, and the 
beds range from 3 to 6 feet in thickness. 

Michigan. 

Graphitic slate, carrying up to 35 per cent of graphite, has been 
mined for a number of years near L'Anse, Baraga county. The material 
is pulverized and air floated, the product so obtained being used in paint 
manufacture. (See page 64.) 

Nevada. 

Graphite suitable for paint, and carrying 30-50 per cent of graphitic 
carbon, is mined near Carson, Ormsby county. 

Rhode Island. 

Graphitic shale has been worked for many years in the vicinity of 
Providence and Tiverton. The Providence material averages 50 per 
cent graphitic carbon, and is in considerable demand for certain classes 
of foundry facing. The Tiverton graphite is employed chiefly in paints. 
Both occurrences consist of graphitized anthracite, and trie material 
is hard and brittle and often carries a large amount of fibrous quartz. 
The alteration of the coal to graphite is regarded as due to regional rather 
than contact metamorphism, and the greatest degree of graphitization 
is observed where the bed has been intensively crumpled and squeezed. 

It is reported 1 that more extensive mining operations for graphite 
have lately been undertaken near Portsmouth, and that a mill for grinding 
and refining the ore has also been erected. 

Miscellaneous Localities. 

In addition to the deposits in the countries mentioned, occurrences 
of graphite are known, and in some cases have been worked in the past, 
in many other parts of the world. Among these may be mentioned Borrow- 
dale 2 , in England; the Alibert mine, west of Irkutsk, in Siberia; Norberg, 
in Sweden; the Marbella mine, Malaga province, in Spain; Cantons Wallis 
and Graubunden, in Switzerland; Senjen, in Norway; Travancore and 
Mysore, in India ; Barrieros, in Brazil; near Ladysmith, in Natal; Pieters- 
burg district, in the Transvaal; Mount Bopple, in Queensland; Munglinup, 
Western Australia; Eyre peninsula, South Australia; Pakawau, New 
Zealand 3 . 



1 Brass World, May 1919, p. 138. 

2 See Special Reports on the Mineral Resources of Great Britain, Vol. V, 1917, p. 27. 
New Zealand Journal of Science and Technology, May 1919, pp. 198-209. 



185 

World's Production of Graphite. 

Complete statistics of the world's annual production of graphite are 
only available to 1913. In that year, a total of 139,283 short tons was 
produced 1 . This total comprises graphite of all grades, and approximately 
one-half of it may be taken as amorphous graphite. Assuming that the 
German and Austrian outputs only kept up to the pre-war level of 1913, the 
total world's output in 1916 probably will not have fallen far short of 150,000 
tons. The increasing importance of Madagascar as a producing country 
is shown by the fact that the production increased from 7,000 tons in 1913 
to 28,000 tons in 1916. **j»! 

The following table and diagram of production for the periods 1913-17 
and 1907-17 respectively, are taken from the reference in the footnote on 
this page : — 




Fig. 43. Diagram showing production of graphite in principal countries in 1907-1917. 
Full lines indicate that bulk of the production is crystalline or flake graphite; 
dotted lines, amorphous. (United States Geological Survey.) 



J Mineral Resources of the United States, 1917, Part II, p. 106. 
67945— 13J- 



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187 



ARTIFICIAL GRAPHITE. 

The chief producer of artificial graphite is the Acheson Graphite 
Company, with plants at Niagara Falls and Buffalo, N.Y., and Niagara 
Falls, Ont. The demand for this class of graphite has grown rapidly, 
and the material now proves an important addition to the supply of natural 
graphite. Artificial graphite is made either from anthracite coal or from 
petroleum coke (see p. 114) and is employed chiefly in lubricants, paints, 
foundry facings, battery fillers, and boiler scale preventives. 

In addition to the bulk graphite produced, there is a large output of 
graphite electrodes, the demand for which has risen rapidly during the 
last three years owing to the great development of certain electro-chemical 
industries and the large increase in the adoption of electric furnaces in steel 
manufacture. There, has been a growing tendency to employ electric 
furnaces in place of crucibles for melting steel, and the production of 
crucible steel in the United States is said to be now only one-eighth of 
that of electric furnace steel. The number of electric steel furnaces in use 
in the United States in 1917 was 223, as compared with 136 in 1916. 

The following table shows the production of artificial graphite in the 
United States from 1899 to 1917 1 :— 

Production of Manufactured Graphite, 1899- 1917 1 . 



Year. 


Quantity. 
Pounds. ' 


Value. 


Price per Pound. 
Cents. 


1899 


405,870 

860,750 

2,500,000 

2,358,828 

2,620,000 

3,248,000 

4,595,500 

4,868,000 

6,924,000 

7,385,511 

6,870,529 

13,149,000 

10,144,000 

12,896,347 

13,633,342 

10,455,139 

(a) 5,580,437 

(a) 8,922,329 

(a) 10, 474, 649 


$ 32,475 
68,860 
119,000 
110,700 
178,670 
217,000 
313,979 
312,764 
483,717 
502,667 
467,196 
945,000 
664,000 
830,193 
973,397 
698,800 
109,102 


8-00 


1900 


8-00 


1901 , 

1902 


4-76 
4-69 


1903 


6-82 


1904 


6-70 


1905 


6-83 


1906 


6-42 


1907 


6-97 


1908 


6-80 


1909 


6-80 


1910 


7-19 


1911 


6-54 


1912 


6-44 


1913 


7-14 


1914 


6-68 


1915 


1-96 


1916 .. 




1917 













(a) Powdered graphite only; electrode material not included. 

The production of artificial graphite at the Canadian plant of the above 
Company from 1906 to 1917, is shown in the following table: — 

Production of Artificial Graphite in Canada, 1906-17 2 . 



Calendar Year. 


Pounds. 


Calendar Year. 


Pounds. 


1906 


445,047 
407,779 
428,540 
513,436 
2,442,166 
2,172,098 


1912 .. 


2,302,625 


1907 


1913 


2,184,472 


1908 


1914 . . 


1,234,239 


1909 


1915 


497,271 


1910 


1916 


525,048 


1911 


1917 


1,096,172 









Mineral Industry, 1917, p. 312. 

2 From returns furnished to the Mines Branch, Division of Mineral Resources and Statistics. 



188 



CHAPTER X. 

DETERMINATION OF THE CARBON CONTENT OF GRAPHITE 
AND GRAPHITE ORES. 

The value of a graphite for most purposes depends essentially on the 
amount of carbon it contains, so that for all practical purposes the determin- 
ation of the latter may be considered sufficient. In certain cases, it may 
be necessary to determine the amount of foreign matter present, and also 
what mineral or other substances this consists of. For crucibles, for 
instance, it is important to know the amount of mica, calcite, pyrite, 
etc., present, since these substances are highly detrimental to the quality 
of the crucibles made from graphite containing them in appreciable amount. 
The presence of silica in graphite for this class of work is not objected to 
for any deleterious quality it possesses, since silica is added to most crucible 
mixtures in any case, and, provided the amount did not exceed the permis- 
sible limit, its presence would not be prejudicial. For lubricating purposes, 
however,' a graphite containing silica is obviously unsuitable, whereas 
mica would not be an injurious impurity. 

Since, however, many commercial uses of graphite call for some sort of 
further treatment of the material as received from the mills, which treat- 
ment often results in a certain amount of waste that cannot be utilized for 
the particular purpose in view and that is disposed of for use in some 
other industry, it is desirable, if only to obviate the necessity of repeated 
analysis, to start out with a product of the highest guaranteed purity 
consistent with cheapness of production. By the various mechanical re- 
fining processes now practised, many of the flake graphites can be brought 
up to a purity of 88 to 92 per cent carbon, and thus a carbon content of 
90 per cent is the standard usually stipulated for by the trade. The 
remaining 10 per cent as a general thing includes varying amounts of 
mica, pyrites, quartz or calcite as the chief mineral substances, and these 
may be eliminated to a certain extent by the further treatment that the 
graphite often undergoes in the factory. 

A number of methods for the determination of the carbon content 
of graphites, as well as for ascertaining the amount of the various impurities 
present, have been proposed. Some of these are rather involved, and take 
too long to have found adoption in general practice. 

The exact method, or combination of methods, to be followed is largely 
dependent on the class of material to be investigated. For instance, to 
determine the carbon content of a high grade sample that can be seen 
to consist for the greater part of graphite, requires a different procedure 
to that where a graphite ore of relatively low carbon content is in question. 

The determination of graphitic carbon with scientific exactness is 
a matter of difficulty, and can, perhaps, not be accomplished satisfactorily 
by ordinary methods. For practical purposes, however, such accuracy 
is not required, and entirely adequate results are obtained by any one of 
the several methods ordinarily employed in commercial practice.. 



189 
Combustion Method. 

In determining the graphite present in a sample of commercial graphite, 
that is to say, of a graphite that has undergone a process of refining and 
has been brought to a purity of between 80 and 90 per cent, the combustion 
method is the one often practised. By this method, the percentage of 
graphite is calculated from the loss in weight of the sample after all of the 
carbon has been burnt off at a high temperature, the process of combustion 
preferably being accelerated by the admission of a current of oxygen into 
the crucible in which the operation is conducted. At such temperature, 
the carbon combines with the oxygen and passes off as carbonic acid gas, 
leaving the impurities in the form of an ash, which is weighed and the 
weight subtracted from that of the sample. 

In employing this method, the following points have to be taken into 
consideration, and the necessary allowance made : — 

1. Hygroscopic water is almost sure to be present, and is driven off 
at a comparatively low temperature. The amount of such water must 
therefore be determined by a preliminary heating. This determination is 
usually made by placing the sample on a watch glass and heating to 110°C 
in the electric oven. 

2. Allowance must also be made for combined water. This is deter- 
mined by igniting the sample in a platinum crucible, well covered to exclude 
air, for one minute at a temperature of 500°-600°C. As a certain small 
amount of graphite may be burnt off during this operation, it is well to 
repeat the procedure a second time, in order to secure a check on this loss. 
Any volatile hydrocarbon present will also be removed at this stage. 

3. Certain graphites contain calcite, or calcium carbonate, and com- 
bustion will drive off carbonic acid gas, which loss will also have to be 
allowed for. The determination of the calcite is preferably to be made 
before combustion, by treating the sample with dilute hydrochloric acid. 
By determining the loss in weight after washing and drying, the calcite 
may be calculated from the amount of lime necessary to combine with the 
carbonic acid expelled. 

4. If iron pyrites or pyrrhotite (the latter is a common accessory 
mineral in Canadian flake graphites) be present, there will be a loss of sulphur 
during combustion. This loss would appear to be frequently overlooked, 
but may materially affect the accuracy of the analysis. The most conven- 
ient way of determining any loss from this side is to treat the sample before 
combustion with dilute nitric acid. This converts the sulphide into soluble 
sulphate. Nitric acid also dissolves any calcite present, so that this 
acid may conveniently be used in all cases where it is not desired to deter- 
mine the amount of such substance. Since the object generally in view 
is to ascertain with a sufficient degree of accuracy merely the graphitic 
carbon content of the sample, and not to determine the nature of the impur- 
ities, the nitric acid treatment is the most convenient, since it dissolves 
both calcite and pyrites, while quartz, mica, and any other silicates present , 
all of which are unattacked, remain in the ash after combustion. 

The above are the principal points that have to be considered in a 
graphite determination, with special regard to the impurities likely to be 
present. The presence of hydrogen, oxygen and nitrogen may also affect 
the strict accuracy of the result, but for all practical purposes, the loss 
in weight from this source may be neglected. Some graphites yield a 
fusible ash, which envelopes the graphite particles and prevents complete 



190 

combustion by excluding oxygen. With such graphites, the combustion 
method is liable to give inaccurate results, and other more involved pro- 
cedure must be resorted to. 

The size of sample usually taken for the combustion method is 0-3 
to 1-0 gram, and the time required for the operation, when a current of 
oxygen is used, from 1 to 2 hours. If combustion in air alone be practised, 
the time for complete combustion will be 2 to 5 hours. The operation 
should take place in a platinum crucible, provided preferably with a per- 
forated lid, the round hole in which measures 5 millimetres in diameter, 
for the insertion of the oxygen feed tube. The sample should be finely 
ground, and the crucible fixed in an inclined position, with the lid so placed 
that about one-fourth of the opening is left uncovered. Heat may be sup- 
plied by a Bunsen burner. 

Combustion is accelerated by exposing a fresh surface of the sample, 
either by turning the crucible occasionally or by stirring with a platinum 
wire. For strict accuracy the crucible should be weighed before and 
after combustion, in order to check any loss of weight. If it be desired to 
analyse the ash of a graphite sample, combustion may be effected in a 
muffle, using a platinum dish instead of a crucible. In this way, a larger 
amount of material may be taken as a sample without unduly prolonging 
the time required for combustion, and a correspondingly larger amount of 
ash is thus secured for analysis. 

The most satisfactory method for commercial practice, working on 
graphites that contain calcite and pyrites or pyrrhotite, as is commonly 
the case with Canadian flake graphite, is probably the following: — 

Reduce the graphite to a powder fine enough to pass an 80-mesh screen. 
Take two samples of equal weight, say from • 5 to 1 • gram. On one sample 
determine the hygroscopic and combined water as follows. First heat to 
100°C-110°C on a watch glass in the electric oven and determine loss = 
hygroscopic water, by weighing. Then ignite in a well covered platinum 
crucible at lower than a red heat, (500°-600° C) for one minute. Weigh 
to ascertain loss = combined water 1 , and repeat the procedure as a check. 
Remove crucible cover to restore atmosphere and get rid of any carbonic 
acid gas formed by the decomposition of carbonates present, replace cover 
and ignite as above for two minutes. Weigh, in order to ascertain 
amount of graphite burnt off in these two minutes, as a check on any loss of 
graphite during two previous ignitions. Boil the second sample with 
15 c.c. of dilute nitric acid, wash, filter on a Gooch crucible and dry at 110°C. 
Weigh, and then ignite at full heat of Bunsen burner in a covered platinum 
crucible in a current of oxygen led in through a tube inserted in an opening 
in the lid. The gas is conveniently passed through a wash bottle or bubble 
tube, in order to control the flow. During combustion, the contents 
of the crucible should be stirred frequently with a platinum wire. Heating 
is continued until the material assumes a light grey colour. Determine 
weight of the ash and deduct from that of the sample before ignition. 

In the case of graphites containing negligible amounts of sulphides 
and calcites, it is not necessary to employ two samples, and the treatment 
with nitric acid may be dispensed with. Most flake graphites of the crystal- 
line rocks, however, contain these minerals, and this is especially true of 
those from unweathered deposits, such as are found in the Grenville series 
of Canada. In these, both silica and sulphides are present in a state of 

1 Any organic and volatile matter will also be removed at this stage. 



191 

microscopic fineness in the flakes, and cannot be removed entirely by any 
process, mechanical or chemical, without destroying the flake form. 

Fusion Method. 

In the case of graphite ores, whose carbon content may range from 
10 per cent upward, determination of the graphite may preferably be made 
by means of fusion with caustic alkali. Such a method has been described 
by Hyde 1 . About 35 grams of caustic potash are melted in a silver crucible 
over a very low Bunsen flame, and • 5 to 1-0 gram of the powdered sample 
is carefully brushed onto the surface of the liquid. The crucible is then 
covered, and the contents allowed to simmer quietly for half an hour. 
After cooling, dissolve the melt in 250 c.c, hot distilled water, and filter by 
suction on a weighed filter, previously treated first with a solution of caustic 
potash and then with hot, dilute hydrochloric acid. After washing the 
graphite on the filter, iron oxide is dissolved with hot dilute hydrochloric 
acid, and the filter with the graphite washed with hot water and dried. 

In place of the caustic potash used above, a mixture of this substance 
and caustic soda may be employed to advantage. 

In the fusion method, it is, however, not always easy to judge when 
the action of the molten alkali is complete, and its power of penetration 
into the graphite would seem to be to some extent dependent on the nature 
of the latter and on the temperature of fusion. Results obtained by this 
method have been found, as a general thing, to be considerably lower than 
those yielded on the same material by combustion, the difference being 
considered as due to loss by oxidation of graphite in contact with red hot 
alkali and to some extent, also, to loss in filtering, etc. The method, 
however, is useful, when the sample contains material that is fusible at the 
temperatures reached in the combustion method, or when a supply of 
oxygen is lacking. It obviates, also, preliminary determinations for 
moisture and volatile matter. Alumina, lime and magnesia, also, may 
be determined in the alkaline filtrate, and iron in the acid washings from 
the graphite residue. 

Absorption Method. 

A second method suitable for use on graphite ores or tailings is the 
absorption method. In this, the carbonates and sulphides are first re- 
moved by boiling the sample with dilute nitric acid. The residue is then 
washed and dried, and ignited in a combustion tube through which a current 
of dried and purified oxygen is passed. The graphite is oxidized, the 
carbon combining with oxygen to form carbonic acid gas, which is passed 
through a drying agent, such as calcium chloride, and then absorbed by 
leading through a previously weighed amount of caustic potash, the carbon 
being calculated from the increase in weight of the latter after combustion 
is complete. The results by this method check satisfactorily with those 
obtained by straight combustion. 

Re-Carbonating Method. 

What is known as re-carbonating is sometimes practised in analysing 
graphites, but the method is inaccurate and unsatisfactory where other 

» Mineral Industry, Vol. IX, 1900, p. 381. 



192 

impurities than carbonates are present, such as sulphides. By this method, 
the sample is ignited in the ordinary way, and after complete combustion, 
the allowance to be made for any carbonates that may have been present 
is determined by treating the ash with a concentrated solution of ammonium 
carbonate, drying and gently heating. The lime present in the ash thus 
is re-converted into the original carbonate form. When sulphides are 
present, however, the loss of sulphur during combustion constitutes an 
error that affects the results. 

Further Notes on Analytical Methods. 

Heinisch 1 gives the following procedure for the qualitative and quanti- 
tative determination of graphite: — 

Qualitative Determination. — For a rough test, in which merely the 
detection of the presence of carbon will suffice, as, for instance, where it is 
desired to distinguish between graphite and other non-carbon substances of 
similar appearance, (e.g. molybdenite), any of the three following methods 
may be followed. (1) Ignite a small, finely powdered sample on platinum 
foil and observe the change of colour that takes place. Molybdenite loses 
sulphur and yields an ash that is at first yellow and later grey, while graphite 
retains its black colour. (2) Treat the powdered sample with dilute 
hydrochloric acid to remove any carbonates present, dry, ignite in a hard- 
glass tube in the presence of a stream of oxygen and pass the gas evolved 
through milk of lime. If graphite be present, a white precipitate of cal- 
cium carbonate will be formed. (3) Mix intimately about 0-1 grams of 
the finely powdered sample with 2 grams of lead oxide and heat in a closed 
glass tube, when, if carbon be present, the lead oxide will be reduced to 
metallic lead. 

For precise results, however, Berthelot recommends the graphitic 
acid test by means of nitric acid and potassium chlorate. This mixture 
has no effect whatever on the diamond, completely dissolves amorphous 
carbon and with graphite yields a greenish-yellow residue of graphitic 
acid, which, on drying, turns brown. The procedure to be adopted in 
making this test is as follows. 

A mixture of 50 c.c. concentrated sulphuric acid with 25 c.c. concen- 
trated nitric acid is placed in a shallow porcelain dish and into it is stirred 
first 1 -25 grams of the finely powdered sample and then, at short intervals, 
22 • 5 grams of potassium chlorate. The mixture should be stirred frequently 
and the chlorate added in small quantities in order to avoid too rapid 
oxidation, which may result in the conversion of part of the graphitic acid 
to carbon dioxide. After no more graphite is visible in the bottom of the 
dish and the evolution of gas has stopped, a small portion of the greenish 
residue may be tested with a solution of potassium permanganate, which 
turns graphitic acid yellow. The contents of the dish are then poured 
into a large beaker of water and allowed to settle, after which the liquid 
is decanted and the residue again washed with water. The wash-water 
usually becomes strongly discoloured, but the resultant loss of graphitic 
acid is small. 

After thorough washing, the residue of green graphitic acid is rendered 
yellow by the addition of potassium permanganate, • 35 grams of the latter 
sufficing for 1 • 25 grams of graphite. The permanganate is first dissolved 

1 Doelter, C, Handbuch der Mineralchemie, Vol. 1, 1912, p. 58. 



193 

in 6 c.c. of warm water, and, after cooling, is mixed with dilute sulphuric 
acid(0-6 c.c. concentrated acid to 3-75 c.c. water), after which it is added to 
the green residue. This operation, also, may take place conveniently in 
a porcelain dish, which is then placed on the water-bath and the contents 
stirred continuously until the red colour disappears. A small quantity 
of hydrogen peroxide is then added, and the whole allowed to stand. The 
graphitic acid is finally washed, first with dilute nitric acid, then with 
alcohol and ether, and is dried in a dessicator. Drying should proceed 
in the dark, since graphitic acid turns brown when exposed to the light. 
The same thing takes place when it is dried by warming. The brown 
colour, however, changes back to green on the addition of concentrated 
nitric acid and potassium chlorate, or to yellow when potassium perman- 
ganate and sulphuric acid are added. Moist, freshly prepared graphitic 
acid is yellow and crystalline. On drying, it forms a sticky, brown, amor- 
phous mass, which is unaffected by all solvents. On heating alone, it is 
rapidly decomposed and glows strongly, leaving a carbonaceous substance, 
which Berthelot terms pyrographite oxide. When the latter is ignited, 
it forms, not amorphous carbon as was long supposed, but graphite. 

If the material to be tested contains much in the way of impurities, 
it is advisable to first fuse it with caustic potash and then treat it with aqua 
regia and finally with hydrofluoric acid. 

In order to detect the presence of coal, coke, charcoal, lampblack, etc., 
in a commercial graphite, the following methods are recommended. The 
material is first powdered, and then heated for some time with concentrated 
nitric acid. If no reddish-brown coloration results, there is no anthracite, 
soft coal, lignite or charcoal present. In order to detect coke, the powder 
is fused with a small amount of sodium sulphate, the fused mass extracted 
with little water and the solution tested with lead paper. If there is an 
important amount of coke present, the paper will turn black, owing to the 
formation of lead sulphide. Graphite itself has little if any reducing action 
on the sulphate. Coke is an active reducing agent for sodium sulphate 
at fusion point, so that the filtered solution of the fused material will contain 
both sodium sulphide and sodium sulphate, according to the proportion 
of coke present. The presence of coke may also be suspected if the sample, 
when treated with dilute hydrochloric acid, gives off sulphuretted hydrogen, 
due to the acid attacking the sulphides generally present in coke in some 
amount. 1 

Should the powdered sample, when heated with concentrated nitric 
acid, yield a reddish-brown solution, this indicates the presence of either 
coal, charcoal or lampblack, or all three. On heating a small amount of 
the material in a closed glass tube, the presence of soft coal or lignite is 
evidenced by the driving off of volatile matter in some quantity. Anthra- 
cite yields only minute amounts of such volatile distillation products, 
while none at all are given off by charcoal. If soft coal alone is present, ' 
and in some amount, the volatile matter will give a decidely alkaline reac- 
tion. Lignite is indicated, if, on heating a small sample of the material 
with dilute nitric acid (1 :10) a solution of a brownish-red colour is obtained. 
To detect lampblack, a sample of the material is extracted with petroleum 
ether. If lampblack be present, a solution -is obtained that is either colour- 
less or only very slightly yellow. On evaporation, this solution leaves 
behind a distinct tarry or smoky smell, due to small amounts of matter 
soluble in petroleum ether that were present in the lampblack. Pure 
graphite is quite unaffected by petroleum ether. 

1 It should be noted that certain graphites also contain sulphides, and thus these tests may not 
be positive. 



194 

Quantitative Determination. — The most accurate method consists in 
burning the finely powdered sample in a current of oxygen, and collecting 
the carbon dioxide driven off. The sample is very finely powdered, then 
boiled in dilute hydrochloric acid to remove any carbonates that may be 
present, washed and dried. From 0-1 to 0-2 grams of the material is 
placed in a clay or platinum boat, which is inserted in the tube of a com- 
bustion furnace and burned in a current of oxygen. The gas driven off 
is led through a weighed tube filled with calcium chloride, which absorbs 
any moisture present, and then into a weighed tube containing soda-lime 
and a small quantity of a dryer, such as phosphoric pentoxide. The 
carbon dioxide is caught in this second tube, which is weighed and the 
carbon content of the sample calculated. Combustion takes 45 to 50 
minutes. Since many graphites contain pyrites or pyrrhotite, it is neces- 
sary to place lead chromate in the combustion tube in order to absorb the 
sulphur dioxide evolved. 

Artificial graphites that contain no chemically combined water or 
other volatile constituents, may be burned in a large platinum crucible 
over the blast, oxygen being led in through a clay tube inserted in a hole 
in the lid. 

In determining the carbon content of a graphite sample by the loss 
in weight after combustion, that is, by weighing the ash, the following 
must be taken into consideration: Any water chemically combined in 
silicates that may be present is not driven off at temperatures below 150°C, 
and if this temperature is exceeded, in order to determine such water as 
loss on ignition, the figures obtained are unreliable. Precaution must 
always be taken against carbonates by treating the sample before combus- 
tion with dilute hydrochloric acid. After drying, the resultant loss is 
determined by weighing, and a portion of the residue is then taken as the 
sample for combustion. If pyrites or pyrrhotite is present, sulphur dioxide 
is liberated on burning, leaving iron oxide in the ash. As 240 parts of 
pyrites yield 160 parts of iron oxide, it is clear that the carbon content 
will appear too high unless the above is taken into consideration. In addi- 
tion, the hydrogen, oxygen, nitrogen, and sulphur content of the graphite 
is a source of minor error. 

Many graphites when burned yield a sinter or fusible ash, which en- 
closes particles of the graphite and protects them from oxidation. In 
such cases, it is advisable to add a small, weighed quantity of well-calcined 
magnesia to the sample. 

In many cases, complete combustion may be effected by burning the 
finely powdered sample in a shallow platinum dish placed in the strongly 
heated muffle of an assay furnace, until the ash turns white. 



195 



APPENDIX. 

Bibliography of Canadian Graphite. 

Geological Survey Publications. 

Bailey, L. W. and Matthew, G. F., Report of Progress, 1870-1, p. 230. (New Brunswick.) 

Ells, R. W., Annual Report, Vol. IV, 1888-9, Part K, pp. 134-9. (Quebec.) 

Ells, R. W., Annual Report, Vol. XII, 1899, Part J, pp. 107-10. (Quebec.) 

Ells, R. W., Annual Report, Vol. XIV, 1904, p. 69J. 

Ells, R. W., Bulletin on Graphite, 1904. (General.) 

Ells, R. W., Geology and Mineral Resources of New Brunswick, 1907, p. 114. 

Hayes, A. O., Summary Report, 1913, p. 242. (New Brunswick.) 

Hoffmann, G. C., Report of Progress, 1876-7, pp. 489-510. (General and analyses.) 

Hoffmann, G. C., Report of Progress, 1878-9, p. 3H. (New Brunswick.) 

Hunt, T. Sterry, Geology of Canada, 1863, pp. 529, 793; 1863-6, pp. 218-23. (General.) 

Ledoux, A., Summary Report, 1915, p. 164. (Quebec.) 

Logan, Sir W., Geology of Canada, 1863-6, pp. 22-27. (Quebec.) 

Osann, A., Annual Report, Vol. XII, 1899, Part O, pp. 66-82. (Quebec.) 

Stansfield, J., International Geological Congress, Guide Book No. 3, 1913, pp. 101-7. 

(Quebec.) 
Vennor, H. G., Report of Progress, 1872-3, p. 178. (Ontario.) 
Vennor, H. G., Report of Progress, 1873-4, pp. 139-143. (Quebec.) 
Vennor, H. G., Report of Progress, 1876-7, pp. 308-20. (Quebec.) 
Wilson, M. E., Summary Report, 1911, p. 283. (Quebec.) 
Wilson, M. E., Summary Report, 1913, pp. 196-207. (Quebec.) 
Wilson, M. E., Summary Report, 1915, p. 156. (Geology of Quebec graphite area.) 
Wilson, M. E., Summary Report, 1916, pp. 214 and 219. (Graphite in Argenteuil County, 

Que.) 
Wilson, M. E., Summary Report, 1917, Part E, pp. 29-42. (Port Elmsley, Ontario.) 
Wilson, M. E., Memoir 113, 1919, pp. 38-43. (Amherst, Que.) 
Young, G. A., and Brock, R. W., Geology and Economic Minerals of Canada, 1909, p. 100. 

(Ontario and Quebec.) 
Annual Volumes, Statistical section, 1885 to 1906. (General and statistical.) 
Catalogue of Economic Minerals of Canada sent to the International Exhibition in 

London, 1862, p. 27. 
Catalogue of Economic Minerals of Canada sent to the International Exhibition in 

Philadelphia, 1876, p. 121. 
Catalogue of Economic Minerals of Canada sent to Colonial and London Exhibition, 

1886, p. 150. 
Catalogue of Section One of the Museum, 1893, p. 134. (List of Canadian graphite 

occurrences.) 
Report of Progress, 1851-2, pp. 42, 118. 
Report of Progress, 1852-3. 
Report of Progress, 1853-6, p. 41. 

Mines Branch Publications. 

Cirkel, F., Graphite, Its Properties, Occurrence, Refining and Uses, 1907. (Monograph 

on Graphite.) 
McLeish, J., Mineral Production of Canada, Annual volumes, 1906 to date. (General 

and statistical.) 
Economic Minerals and Mining Industries of Canada, 1913, p. 46. (General.) 
Report on the Mining and Metallurgical Industries of Canada, 1907-8, pp. 404-7 and 

496-9. (Ontario and Quebec.) 
Spence, H. S., Summary Report, 1916, p. 34; 1917, p. 49. 

Miscellaneous. 

Canadian Mining Institute, Journal and Transactions: 
Bateman, G. C, Vol. VIII, 1905, pp. 343-7. (General.) 
Brumell, H. P., Vol. X, 1907, pp. 85-104. (General.) 



196 

(General.) 
P., Vol. XII, 1909, pp. 205-17. (Concentration.) 
Brumell, H. P., Vol. XXII, 1919. (Concentration.) 
Cirkel, F., Vol. XV, 1912, pp. 261-9. (Quebec.) 
Greenland, C. W., Vol. XVI, 1913, pp. 584-97. (Carbonaceous schists of Lake of the 

Woods.) 
Stansfield, J., Vol. XVI, 1913, pp. 401-11. (General.) 
Wilson, M. E., Vol. XIX, 1916, pp. 362-8. (Quebec.) 



Annual Reports of the Department of Mines, Province of Quebec, 1891 to date. 

Annual Reports of the Ontario Bureau of Mines, 1896 to date. 

Canadian Mining Journal: Vol. XXIX, pp. 15-18; 70-2; 361-3. 

Canadian Mining Journal: Vol. XXX, pp. 267-72. 

Canadian Mining Journal: Vol. XXXIII, pp. 433-7. 

Canadian Chemical Journal: Vol. Ill, No. 7, July 1919, pp. 213-6. 



INDEX 



PAGE 

Acheson Graphite Co 114, 158, 187 

Oildag Co 167 

Air classifiers 73 

Alabama: graphite deposits 181 

Graphite Producers' Association 182 

Alaska: graphite deposits 183 

Allan, J.G. — mining operations, Denbigh township 39 

Alibert mine 184 

Alkow harbour B.C. — graphite occurrence 22 

American Graphite Co. — largest producing mine in United States 182 

use of buddies 81 

" " " Callow system 88 

Amherst township: graphite property 46 

Amorphous graphite: characteristics 9 

" " manner of treatment 63 

Analysis: Canadian graphites 15 

" carbonaceous schists, Lake of the Woods 41 

" Ceylon and Ticonderoga graphites 16 

" Low township graphite ^ . . . 59 

" New Brunswick graphite 23 

" North Elmsley township graphite 32 

" Nova Scotia graphite 24 

Anglo-Canadian Graphite Syndicate 54 

Aquadag , 115 

Argenteuil county: graphite deposits 43, 44, 61 

Artificial graphite 114, 187 

Ashby township: graphite ore 39 

Ashland wet box 101 

Australia, South: graphite deposit 184 

West: " " " 184 

Austria: graphite deposits 174 

B 

Baffin island: graphite deposits 18, 61 

Bedford township: graphite occurrences '. 26, 41 

Beidelman and Lyall: graphite operations 39 

Bell Graphite Co 50 

" mine 50 

" R. — specimens received from Baffin island , 61 

Bessell Bros. — process of refining 113 

Bibliography of Canadian graphite 195 

Big island: specimens from 61 

Black Donald Graphite Co 35, 36 

" " " use of buddies 81 

" mine 18, 25, 35 

" " " exceptionally rich 36 

Black Lead island: specimens from 61 

Blithfield township: graphite deposit 41 

Boiler graphite: use of to prevent scale 160 

Borrowdale: graphite mines 3, 145, 184 

Bound Brook Oilless Bearing Co 157 

Brazil: graphite deposit 184 

British Columbia: graphite in — 18, 22 

Brochadon process chemical refining 113 

Brodie's process chemical refining. 112 

Brougham township: graphite deposits 35 

Brumell's wet box 106 

Brushes, graphite: use of graphite for 151 

Buckingham Graphite Co.— operations of 42, 43, 53, 54, 55 

" township: chief deposits of Quebec in 43 

" " graphite deposits 18, 48 

Buddies 80 



197 



198 
c 

PAGE. 

California: graphite deposits 184 

Callow system: result of tests 90 

Calumet Mining and Milling Graphite Co 44 

Canada Paint Co. — graphite deposits in New Brunswick worked by 23 

Canada Plumbago Co 42, 54 

Canadian Graphite Co. — property in Wentworth township 46 

" " industry — production, exports, imports, etc 162 

Cape Breton island: graphite occurrences 24 

Carbon content of graphite, determination of 188 

Carbonaceous schists 41, 42 

Cardiff township: graphite occurrences 26 

Ceylon: graphite deposits 175 

Chatelain, Rev. Father: graphite property 61 

Chemical refining of graphite 112 

Chosen: graphite deposits. See Korea. 

Claxton, J. — mining operations by 58 

Clays for crucibles 125 

Cole, A. A. — description of Quebec graphite deposits 43 

Colmer washer 102 

Colorado: graphite deposits 184 

Concentrates: refining of , 110 

Concentration by dry methods 67 

wet " 80 

" miscellaneous systems * 108 

Consolidated Graphite Mining and Milling Co 57 

Crucibles: Ceylon graphite in demand for 175 

" comparison of clays for 125 

" large consumption of graphite for 119 

" manufacture of 131 

" standard sizes 140 

Crystalline graphite: characteristics 9 

Cummings, Dr.— graphite property 58 

D 

Darling township: graphite occurrence 41 

Davis, M.P. — graphite mine 57 

Deflocculation process 114, 115 

Denbigh township: mining operations 39 

Diamond Graphite Co 57 

Dickson, H. — graphite property 61 

Dominion Crucible Co 167 

Graphite Co 52 

" mine 52 

" of Canada Plumbago Co 55 

Douglas Bros. — process of refining 113 

Dry batteries: use of graphite for 150 

Dungannon township: graphite occurrence 41 

E 

Earle and Jacobs - graphite operations 57 

Edwards, W. C. — graphite property 61 

Electrodes: use of graphite for 154 

Electrostatic machines 78 

Electrotyping: use of graphite for. . . 150 

England: graphite deposits ; 184 

Evans, William: mining operations in Low township 60 



Ferraris tables. See Krupp-Ferraris. 

Film flotation: modified form of 10 

" " . See Surface tension. 

Fitzgerald, A. J. — monograph on artificial graphite 115 

Flake graphite: characteristics 9 

" " manner of treatment I 64 

Flotation as method of concentration 86 

Foundry facings: use of graphite for 149 

Frontenac county : graphite occurrences. 26 

Frothing oil flotation 86 



199 

G 

PAGE. 

Gatineau Graphite Co.— prospecting by 58 

General Engineering Co. — concentration tests 39, 93, 94, 95 

Germany : graphite deposits 177 

Globe Graphite Mining and Refining Co.— graphite property, North Elmsley 29 

Globe Refining Co. — mining operations 29 

Glutrin * 149 

Graphite : amorphous, meaning of term : 6 

artificial 8, 15 

chemical and physical properties 4 

composition of ores 13 

concentrate from Low township mine 60 

concentrating and refining of 63 

concentration: summary Ill 

domestic consumption 167 

electrodes: manufacture of 114, 119 

general review of the industry 167 

geology of 31 

history of 3 

in Canada 18 

Limited, mining operations of 46 

made from anthraeite coal 114 

" carborundum 114 

market conditions in United States 171 

mining, inception in Quebec province 42 

" methods 21 

mode of occurrence 9 

name first given 4 

origin 11, 32 

origin of, three hypotheses • 20 

other names for 

percentage of in ores 16 

principal part of world's production amorphous 16 

production of in Canada 18, 162 

" in Quebec 44 

Products, Limited: graphite property 46 

specific gravity. •. 5 

" heat 5 

subsidiary uses 160 

types of deposit 19 

uses of 119 

world's production of . . , 185 

" supply sources 174 

Grenville township: first graphite mining in 42 

graphite deposits 44 



Haliburton county: graphite occurrences 26 

Hardman, J. E. — graphite property, Buckingham 49 

Harrison lake, B.C. — graphite occurrence 22 

Harwood, R. V. — Miller mine worked by 45 

Hayes, A. O.— New Brunswick graphite described by 23 

Hirsch, S — graphite property, Grenville township 45 

Historical 3 

Hoffmann, G. C. — analyses of Canadian graphite 15, 42 

" " " New Brunswick graphite 23 

Hogg lot 52 

Hooper pneumatic concentrator > 69 

Hudson Bay Co. — development work Baffin island 62 

Huff electrostatic separator 79 

Hull county : graphite deposits 58, 61 

Hunt, T. Sterry: graphite discussed 42 

I 

India: graphite deposits 184 

International Graphite Co 115 

" Mining Co.— first operators in Ontario 29 

Introductory 1 

Italy: graphite deposits 178 

J 

James tables 85 

Joker claim, Baffin island 62 

67945—14 



200 



x PAGE. 

Kendall separator 89 

Keystone Graphite Co. — Miller mine worked by 45 

King Bee mill. ^ 75 

Korea: graphite deposits . . 177 

Krom pneumatic jig .' 68 

Krupp-Ferraris tables 85 

L 

Labelle county: graphite property 46, 61 

Labouglie, J. — classifier patented by 74 

Mr. — mining operations Buckingham township 50 

Labrador: graphite found in 18 

Lake of the Woods: carbonaceous schists of. 41 

Lanark county: graphite deposits 28 

Latimer, J. F. — system of concentration devised by 89 

Lochaber mill equipped with buddies 89 

Lochaber Plumbago Co 42, 58 

" township: graphite in 42, 58, 60 

Log washers 83 

Logan, Sir Wm. — reference to graphite in early report 42 

Loughborough township: graphite occurrence 41 

Low, A. P. — graphite occurrences Baffin island, etc ...... ._ 61 

" township: graphite deposits 58 

Lubricating: use of graphite for 155 

Luzi's process of refining 113 

Lyndoch township: graphite occurrences 39 

M 

McConnell, Binaldo: mining operations by 29, 36 

McHale, Mr. — mining operations, Lyndoch township 39 

McLean and Fitzsimons: graphite property, Low township 58 

Madagascar: graphite deposits 178 

Maniwaki Indian reserve: graphite on 60 

Marbella mine 184 

Marmora township: graphite occurrence 41 

Matthew creek, B.C. — graphite occurrence 22 

Mechanical washers , 83 

Mexico: graphite deposits 180 

Michigan: graphite deposits ; 184 

Miller, E. C. — antifriction alloy proposed by 158 

" mine: earliest to be exploited 45 

" Mr. — mining operations by 58 

Minerals separation system of concentration 98 

Mines Branch: concentration tests 95 

Mining Corporation of Canada: graphite property 26 

Molybdenite: confused with graphite 3 

Monmouth township: graphite occurrences 27. 

Montana: graphite deposits 183 

Monteagle township* workings in 26 

Montreal Plumbago Co 42, 54 

Morgan Crucible Co. — graphite bearings and bushings 158 

brushes -... 151 

Multipar Syndicate: operations of 46 

Munro washer 101 

N 

Nappenberger separator 74 

Natal: graphite deposit 184 

National Graphite Co. — operations in Cardiff township 26 

" Grenville township 45 

Monmouth township. . '. 28 

Nevada: graphite deposits '. . . . . 184 

New Brunswick: graphite production 22 

New England Plumbago Co 42, 48 

New Quebec Graphite Co. — operations Buckingham township 48 

New York Graphite Co. — operations in Cardiff township 20 

graphite deposits 182 

New Zealand: graphite deposit 184 



201 

PAGE. 

Nigrum bearings 157 

Norberg graphite deposit 184 

North American Graphite Co 43, 54 

" mine 54 

North Burgess township: graphite deposits 28, 41 

" Elmsley township: graphite deposits 29, 41 

Northwest territories : graphite found in 18 

Northern Graphite Co. — operations in North Elmsley 29 

Norway: graphite deposit 184 

Nova Scotia: graphite occurrences 24 

O 

Oil flotation: advantage of 43 

Oildag 115 

Ontario Graphite Co ' : 36 

" graphite deposits in ". 25 

" production of graphite in 25 

P 

Paint: use of graphite in 158 

Patents: United States, oil flotation 90 

Patterson, T. W. — graphite property, township Gore 46. 

Pencils 144 

Pennsylvania: graphite deposits 183 

Peerless Graphite Co 57 

Petroleum coke: artificial graphite made from 114 

Plumbago: manner of treating 63 

" see Crystalline graphite. 

Syndicate, operations by 52 

Pontiac county: scattered deposits of uneconomic importance 43 

Powder glazing: use of graphite for 160 

Pritchard process chemical refining , 112 

Pugh and Weart: mining operations 42, 53 

Putz, H. — system of concentration 108, 109 

Pyne, R. A. — operations in North Elmsley 29 

Q 

Quebec Graphite Co. — property Buckingham township 48 

Quebec province: graphite mining in 42 

Queensland: graphite deposit 184 

R 

Rae and Co. — Miller mine worked by 45 

Rake washers 84 

Refining of graphite concentrates .110, 112 

Refractory products, other 144 

Reilly and Layfield: mining operations 46 

Renfrew county: graphite deposits 35 

Rhode Island: graphite deposits 184 

S 

Schlossel method chemical refining 112 

Schurecht, H. G.— see Stull. 

Shot polishing: use of graphite for 160 

Siberia: graphite mine 184 

Simplex system of concentration 99 

South Africa: graphite deposit 180 

South Canonto township: graphite occurrence 41 

Spain: graphite deposits 180 

" " mine 184 

Stewart pit 52 

Stove polish: use of graphite for 159 

Stull, R. T., and Schurecht, H. G.— briquetting of flake graphites 109 

Surface tension system of concentration 101 

Sutton, Steele and Steele dry jig table 71 

" " separator 79 

Sweden: graphite deposit 184 

Switzerland: graphite deposits 184 



202 



PAGE. 

Tests of graphite: General Engineering Co 93, 94, 95, 97 

Texas: graphite deposits 184 

Timmins, N. A.— graphite operations in North Burgess 28 

TOch, M. — graphite paints 159 

Tonkin-Dupont Graphite Co ; 26, 27 

Torrance, J. F. — reason for stagnation of industry. 42 

Transvaal : graphite deposit 184 

U 

United States Graphite Co. — manner of treating amorphous graphite 64, 147 

" " " deposits in Mexico 180 

" " graphite deposits of 181 

Uses of graphite — 119 

V 

Vennor, H. G. — graphite occurrences described 42 

Virginia Graphite Co 27 

W 

Walker mine 55 

" Plumbago Mining Co 43 

" W. H. — operations by 55 

Ward, J. K., estate of: graphite property Grenville township ' 44 

Weart, S. J. — graphite property, Buckingham 53 

Wentworth township: graphite deposit '• 46 

West and Company: shipment of Buckingham graphite 53 

Westmeath township: graphite occurrence 41 

Wet tables : 85 

Winkler method chemical refining 112 

World's production of graphite 185, 186 



Plate I. 




Typical high grade, Canadian flake graphite ore, 15-20 per cent carbon, from 
the Buckingham district, Que. 



67945—15 



Plate II. 




'■-->.-■; . 



Foliated plumbago, range III, lot 18, township of Low, Que. This plumbago is 
of good quality, but is hardly as dense as that from Ceylon. 



Plate III. 




Fibrous or columnar plumbago, range VII, lot 21, township of Buckingham, 
Que. Narrow veins of such material are not uncommon in the Buckingham 
district, usually in the more or less immediate vicinity of bodies of flake ore. 

67945— 15y 2 



Plate IV. 




Radiated, lamellar crystals of graphite penetrating a narrow band of highly 
silicated limestone enclosed between two pegmatite stringers. The original limestone 
has been almost completely altered to a mixture of granular quartz and feldspar, with 
subsidiary sphene and pyroxene. From range III, township of Low, Que. 



Plate V. 




T77 



iprrprri 



Foliated plumbago, developed along the contacts of pegmatite stringers with a narrow zone of 
crystalline limestone (C). In this instance, the limestone has been only slightly silicated, and very 
little flake graphite occurs disseminated through it. From range III, township of Low, Que. 



^<A 




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Plate VIII. 




Method of working graphitic limestone ore-body, concession XIII, lot 23, 
township of Monteagle, Ont. 



X 




Plate XI. 




100-foot level at mine of Globe Graphite Mining and Refining Company, 
concession VI, lot 21, township of North Elmsley, Ont. The pillar indicates 
the thickness of the ore-body in the east workings. 



Plate XII. 







" Needle-flake" graphite ore, from concession VI, lot 21, township of North Elmsley, Ont. 



Plate XIII. 




Mill of the Globe Graphite Mining and Refining Company, Port Elmsley, Ont. The 
mill is driven by water power. 




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taken August, 1919. The ore-body at this point has a width of 
seventy feet. (See Fig. 4.) 



Plate XVI. 




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Plate XXI. 




Exceptionally large sized graphite flakes, from range IV, township of Buckingham, 
Que. The flakes, measuring up to 5 inches across, occur [at the contact of a 
pegmatite dike with gneiss. 




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Plate XXIV. 




Dike of pegmatite (anorthosite) A intruded into gneiss B, range VIII, lot 20, 
township of Buckingham, Que. Flake graphite is developed in the gneiss along 
its contact with the intrusive. 




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Plate XXVII. 




Sectional view of Raymond high-side mill and separator. 
(Raymond Bros. Impact Pulverizer Company, Chicago.) This 
machine is used for grinding amorphous graphite. 




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Plate XXIX. 




Krom pneumatic jig. (Krom Machine Works, 170 Broadway, New York.) 



Plate XXX. 




Hooper pneumatic concentrator. (Ticonderoga Machine Works, 
Ticonderoga, N.Y.) 



Plate XXXI. 




Type of rolls used in Canadian mills employing the 
dry concentrating process. (Wm. and J. G. Greer, 
Toronto, Ont.) 




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Plate XXXIII. 




Sutton, Steele and Steele di-electric separator. (Sutton, Steele and Steele, 
Dallas, Texas.) The machine illustrated has three pairs of electrodes. 



67945—17 



Plate XXXIV. 




Details of Sutton, Steele and Steele di-electric separator. A connexion to 
generator, B connexion to ground, C revolving electrode, D needle elec- 
trodes, E tailings, F middlings, G concentrates, H roller to remove particles 
adhering to electrode C. 






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Plate XXXVII. 



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Photo, New Quebec Graphite Company, Buckingham, Que. 



67945—18 



Plate XXXVIII. 




Mixer arranged for belt drive. 



Plate XXXIX. 




FRONT VIEW 



Mixer arranged for motor drive. 

Machines for mixing crucible bodies. (Crossley Machine Company, 
Trenton, N.J.) The upper mixer has a capacity of % ton, and the 
lower 23/2 tons, per hour. 



Plate XL. 




Pull-down and jigger used m making crucibles. (Crossley Machine Company, 
lrenton, N.J.) The illustration shows the profile or tool in position to be lowered 
into the mould by means of the right-hand wheel. The left-hand wheel controls the 
movement of the tool horizontally, in order to press the clay against the wall of 
t>ne mould. 



67945—184 



Plate XLI. 




Pull-down and jigger used in making crucibles (Crossley Machine Company, 
Trenton, N.J.) The profile or tool is here shown lowered into the mould. 



Plate XLII. 




Crucibles as removed from the moulds. (Crossley Machine Company, 
Trenton, N.J.) 



Plate XLIII. 




Types of crucibles used in melting non-ferrous metals. (Joseph Dixon 
Crucible Company, Jersey City, N.J.) 



Plate XLIV. 




Types of crucibles used in tilting furnaces. (Joseph Dixon Crucible 
Company, Jersey City, N.J.) 




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Plate XLVI. 




Type of crucible used in melting steel. 
(Joseph Dixon Crucible Company, Jersey City, 

N.J.) 



Plate XL VII. 




Bottom-pour crucible for preventing oxidized 
metal and other impurities getting into castings. 
(Joseph Dixon Crucible Company, Jersey City, 

N.J.) 



Plate XLVIII. 







Brazing crucibles, for dip-brazing. Below, 
graphite boxes, for case-hardening, carbon- 
izing, etc. (Joseph Dixon Crucible Com- 
pany, Jersey City, N.J.) 



Plate XLIX. 




Type of retort, used in the smelting 
of gold, silver, zinc, etc. (Joseph Dixon 
Crucible Company, Jersey City, N.J.) 



Plate L. 




Funnel or extension tops, for increasing the capacity of crucibles, and 
pyrometer shields. (Joseph Dixon Crucible Company, Jersey City, N.J.) 



Plate LI. 




Types of graphite stoppers and nozzles for steel-pouring ladles. (Joseph 
Dixon Crucible Company, Jersey City, N.J.) 



Plate LII. 




Types of phosphorizers used in the manufacture of phosphor bronze. 
(Joseph Dixon Crucible Company, Jersey City, N.J.) 



Plate LIII. 




Types of stirrers, skimmers, and dippers. (Joseph Dixon Crucible Company, 
Jersey City, N.J.) 



Plate LIV, 





ci 



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fi 



Types of graphite commutator brushes. (United States 
Graphite Company, Saginaw, Mich.) 



Plate LV. 



?Y 




1 1 









J 




Types of Nigrum oilless bushings. (Bound Brook Oilless Bearings Company, 
Bound Brook, N.J.) The bushings are of hardwood, impregnated with a graphite 
lubricating compound. 



Plate LVI. 




Types of Bound Brook oilless bushings. (Bound Brook Oilless Bearings Company, 
Bound Brook, N.J.) The bushings are cast with grooves, which are afterwards 
packed under hydraulic pressure with a graphite lubricating compound. 




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